Freshwater Fishpond
Freshwater Fishpond
Freshwater Fishpond
"
Peace Corps
\YITAJ
PULCATION
by
Marilyn Chakroff,
PEACE CORPS
ACTION/PEACE CORPS
PROGRA1 & TRAINING JORNAL MANUAL SERIES NLMBER 11
VOLLUrEERS IN TECHNICAL
ASSISTANCE
VITA PUBLICATIONS VANUL SERIES NLIER 3EE
September, 1976
May be re,,roduced without payment of royalty for offic ial U.S. Government purposes.
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(iv)
REPLY FORM
For your convenience, a reply form has been provided here. Please
send it in and let us know how the manual has helped or can be made
more helpful. If the reply form is missing from your copy of the
manual, just put your connents, suggestions, descriptions of problems,
etc., on a piece of paper and send them to:
FISH POND CULTURE
3706 RHODE ISLAND AVENUE
MT. RAINIER, MD. 20822
U.S.A.
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LEFT B
L=F
iU
Date
Your Name Your Address
Your Company or
Agency, if any
1. How did you find out about the PC/VITA Freshwater Fish Pond Culture
and Management manual? How did you get your copy?
2. Which parts of the manual have you found most useful? Why?
Least useful?
(vii)
3. Did you find the manual easy to read, too simple or complex,
complete or incomplete?
7. What were your successes using the manjal or implementing any of the
plans or procedures? Problems? Please describe completely.
(viii)
Table of Contents
Section "About This Manual" Reply Form 1 2 3 4 5 6 7 8 9 10 INTRODUCTION PLANNING: PLANNING: THE SITE AND THE TYPE OF FISH FARM SELECTION OF FISH Page iii
vii
1
11
33
53
79
107
149
157
165
175
181
185
191
FISH POND CONSTRUCTION PREPARING THE POND MANAGING THE POND HARVESTING THE POND PRESERVING FISH PROBLEMS OF FISH IN PONDS OTHER METHODS OF FISH CULTURE Glossary Resources Measurements Used in This Manual
(ix)
Introduction
-l
A r\ "--l-
If the farmers inyour area already eat a lot of fish, or like fish, fish
farming for food may not be hard to introduce and have accepted.
If they do not eat fish often, you will have to keep this when
you talk about fish as a healthy food. Food just may not in mind most
important reason, from their point of view, for wanting to be the fish.
grow
17 16 20 20
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C4
67
67
26
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14
11
11
9
37
21
22
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2
9
7
3
These values are estimates only; the amount of protein varies according to the age, size, and quality of the food, and how it was cooked and stored.
SouAce:
But there are other reasons you can offer a farmer. For example, a
farmer may consider cultivating fish if he realizes
that fish a;'o easy
to grow, cheaper than some kinds of meat, available as food all round, etc.
You will have to see which combination of arguments year
works
best for getting farmers interest(d.
BETTER LAND USE Some farmers may be more interested in when they realize they can accomplish two purposes: provide fish farming a reliable food supply and make the best possible use of their land.
"Fish farming" is a good thing to call "fish culture" because
it can
start the farmer thinking about raising fish with the same kind of plan ning and land-use management ideas that he puts into raising crops.
Whether the farmer raises fish, crops,
animals, he is using or his land
in certain ways. His aim in all cases is to increase the production
food and the yield from the land. What farmers, and other people, of
often
do not realize is that fish culture can
help get more out of the land.
Here are a few ways in which fish culture can help support and extend a
farmer's land use:
Land gets tired when it is used for growing the same crop
year after year. These crops use up nutrients in suil, and
they begin to grow poorly. Fish ponds can be built on
this
land and fertilized to provide food for the fish.
After a
few years of fertilizing and growing fish, the soil
inside
the pond regains some of the nutrients used up by the grow ing of crops year after year. The land can then be used for
crops again.
Some farmers own land that may not be very crops: it is too sandy, for example. But building fish ponds in sandy soil.
So the able to use land that was once not of much good for growing
there are ways of
farmer would be
value to him.
There are many ways that fish farming can fit into the
farmer's plan for his land.
The important thing is that all
of these ways help the farmer make the best use and get more
out of what he has -- readily, and often without much expense.
For example, a farmer who grows paddy rice can grow fish in
that paddy; fish ponds can be built as part of water supply
and irrigation systems; vegetable scraps and animal manures
can be collected and used for fertilizing ponds. The farmer
should know that a farm with a fish pond or ponds can give
a total food yield that is higher than a farm with no fish
ponds.
The following diagram illustrates
some of the ways in which the fish
pond fits into the farm: The same water source is used by both the
garden and the fish pond; the mud from the bottom of the pond makes
good fertilizer for the garden; vegetable matter trom the garden can be
used to fertilize fish ponds;manure from the animals can be used for the
pond and parts of fish can be used to feed animals; etc.
Vrmanure
VEGETABLE GARDEN
4--.or
GARDN
.wases c9reens
iIo~t =rmud~
oren wcite
an wate ~ ~water
ALS
.4
FiSH
t_
POND
ADDED INCOME Fish ponds can be quite small, or they can be large. They can be made using expensive equipment and drainage systems, or they
can be dug using hand tools and drained by a bamboo pipe. Fish can grow
successfully in both of these types of pond, as long as the ponds are
managed correctly.
If the major reason for building the fish pond is to get increased and
better food for his family, a farmer certainly does not need fancy ponds
or expensive equipment. Fish ponds can be very inexpensive to keep.
Fish do not require fancy foods. Many ponds provide all the food the
fish need. But besides the foods they find in the water itself, some fish
eat leafy garbage, mill sweepings, beer residues, spoiled grains, broken
rice, and many other waste products that might not otherwise be used.
v-.
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//
Before construction can begin, the farmer must look over his land to choose the place or places where ponds can be built, and decide what
kind and how many to build. He must also decide on the kind of fish
culture he wants to do, and on the type of fish that he wants to raise.
He must look at his resources and his needs very carefully before he actually begins building and operating a fish pond. This section will give information to guide the farmer in the planning of ponds and kind of fish culture.
TOPOGRAPHY j5sL
WATER SUPPLY
oi'TYPES OF
~FlH
The Site
One of the most important parts of planning is flnding the right place
(selecting the site) for the pond. Fish ponds use the land ina different
way from agricultural crops such as rice or wheat, but fish also are a
crop. And when a farmer builds a fish pond, he ischoosing one use of
12
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60L 6"ah
13
There are three factors that work together to make a good site for a
fish pond:
* Water supply
Soil
Topography
WATER SUPPLY Water supply, sotl, and topography all are important,
but water supply is the most important factor in selecting a site. Fish
depend upon water for all their needs: fish need water in which to
breathe, to eat, and to grow and reproduce. If a site has water avail able year-rounA, that site meets its first test easily. Ifwater is not
available all the time but there is some way to store water -- in large
tanks, barrels or drums, in depressions, ponds, or wells -- for use when
the natural water supply is low, then that site may still be all right.
The key, of course, is that water must be available at all times and in
good supply.
Where Can Water for Fish Ponds Come From? from many sources:
-
Ran natL.
to fill
Some ponds, called "sky" ponds, rely only on rainfall their need for water.
* Run-o66.
Some ponds are gravel and sand pits which fill when water from the surrounding land area runs into them. Most ponds are filled with water that comes
from natural springs or wells, or with water that has been
channelled (diverted) and brought in from streams, rivers,
or lakes.
Some ponds are built where there is a spring to supply water. Spring water is water under the ground that has found a way to get out. It leaves the ground and becomes a stream as it flows away. Spring water is good for fish ponds because it is usually clean (uncontaminated) and has no unwanted fish or fish
* Natut uzteitz.
* Spvktg3.
ILIN~
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--
WATER Lu1Li't
WALLN
f/A,
tRA
14
eggs in it. Ifthe water from a spring has travelled very far,
Itmay need to be filtered before it is used for a fish pond.
But filtering is easy to do (see the OConstruction " section)
and the important fact is that the water supply isavailable.
WeM. The best source of water for a fish pond iswell water.
Well water has few contaminants and, if the well is a good one,
the water iscontinuously available. Well water and spring
water, however, are both often low inoxygen content. Fish
need to have oxygen in their water to live. Since this problem
isovercome easily (see water quality information in the section
on "Preparing the Pond") the major factor to be considered
here isan adequate water supply.
Most fish ponds use water that comes from a stream, river, or lake.
A d'version ditch or channel is dug between the water source and the
poni to take water from source to pond. This is a good way to fill a
pon0 because the water can be controlled easily. When the pond isfull,
the channel can be blocked with a gate or a plug (see "Construction"
section), and the water will stop moving into the pond.
There can be problems with this kind of water supply; for example, often
in tropical areas streams flood in the rainy season. This extra water
can be dangerous to the pond and must be diverted away from the pond by
a channel built for that purpose. IT IS BEST NOT TO CHOOSE A PLACE THAT
IS KNOWN TO FLOOD WHEN CHOOSING A WATER SUPPLY AND SITE FOR A POND. When
a pond floods, all the fish escape and the pond isempty at harvest time.
If the water for the pond is being taken from a stream, lake, or river,
then the farmer should plan to filter the water carefully when filling
the pond. Water from these sources sometimes contains unwanted fish or
fish eggs. Filtering prevents these fish or eggs, and other harmful
.. au-imals, from entering the pond.
uality of the Water SuP 1. Finding an adequate water supply is the
irst step. Then the armer has to check that supply to make sure it
can be used for a pond. This check of the water should include:
looking at the water, smelling itand tasting It.
looking to see ifthere isa family upstream who take baths in
the water before itgets to the pond.
making sure that there isno family or village downstream that
depends upon the source for their drinking water.
If the water supply seems all right, the farmer must also find the
answers to some other questions. Where the water comes from, how far it
travels to get to the site for the pond, and what kind of soil it travels
over will all affect the quality of the water. These questions and their
answers tell what must be done to make the water right for a pond:
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Is the water very clear? Then the farmer may have to fertilize
the pond because there are not enougn iiu'rients in the water.
Is the water very muddy? Then it will have to settle before it
is used in the pond: a special place will have to be made
where the mud can settle out of the water before the water
goes into the pond.
Is the water a bright green? food in it.
It probably has a lot of fish
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If it holds its shape when the farmer cpens his hand, it will
be good for a pond. Remember, the more clay in the soil, the
better it is for building a pond.
If the soil is sandy, or does not contain much clay, the farmer can still
build a pond. There are ways of building ronds in these soils. But he
should be aware that building a fish pond in such soils requires more
effort and may not be as successful. Digging test holes will tell the
farmer what his soil is. Larger ponds can be built in soils with clay. If the soil is rocky or has
shifting sand, etc., only small ponds are possible. If there are other
locations available, the farmer would be wise to see if there is another
place with soil better suited to the fish pond. More information on soil
is included in the "Construction" section.
Ability of Soil to Provide Nutrients. Soil also contributes to the pond's
fertility. Fertility is a measure of the nutrients in the pond, and it
simply refers to how much food there is available in the pond for the
fish to eat. A very fertile pond is one which contains a lot of fish food.
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The soil of the pond contains some of these necessary nutrients -- like iron, calcium, and magnesium. In addition, however, soil also can contain
acids; these substances often are harmful to fish. Whatever a soil has
in it is drawn into the pond by the water and thus comes in contact with
the fish. Somet;mes after a heavy rainstorm, there are big fish kills
in new ponds. This happens because the heavy rain carries larger
amounts of acids from the soil into the pond. So the farmer who is aware
of the kind of soil he has for his fish pond can prevent this problem
before it happens.
REMEMBER: One good Indicatcr of the quality of soil Is whether it has
been used for growing crops. If crops grow well in that location, the
soil will probably be good for the fish pond. If crops did grow well
there before the nutrients were used up, then it will probably still be
free of harmful substances.
TOPOGRAPHY The third factor in site selection is topography.
Topography is a word used to describe the shape of the land
whether
-it is flat or hilly, upland or lowland, etc. The topography of the land
determines the kinds of ponds which can be built.
Ponds can be built in
valleys or on flat ground. They can be square or rectangular, or uneven
in shape. They can be large or small. All of this is determined by
topography of the land, as well as by the farmer's requirements.
The most useful topography for fish ponds is that which allows the farmer
to fill and drain ponds using gravity. Ponds built on a slope, for
example, can be drained easily. If ponds are located on flat land, the
pond must be built with a slope inside it so it can be drained by gravity,
or it will have to be drained using a pump.
.S_
the farmer looks at a hillside, he can see that It rises. It
.g.If s gher at cne point than at another. This difference in height, from
high to low point, is the slope of the land. In more scientific terms,
slope is the relationship between the horizontal distance (length) and
the vertical distance (elevation) over a piece of land.
Slope Is usually written as a ratio (1:2) or as a percentage (5%). A
slope of 1:2 means that for every change in length of 2 meters, there Is
a change of 1 meter in height. A slope of 5% means that for every change
in length of, say, 100cm, there is a change in height of 5cm. Pond
bottoms usually have a slope of 2-5%, whether they are on level ground
or in a hilly area. As long as the pond bottom has a slope, it can be
drained completely.
A far 2r does not require a scientific understanding of slope to build
a pond. He does need to know how the shape of his land determines the
best place for building ponds. Ponds built in hilly places often are
made part of the hill. The picture on top of the next page, of a pond
with a spring as a water source, shows how the slope of the land has
been used to set up the pond's drainage system.
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19
A NOTE OF CAUTION 5 fore a farmer even begins, however, it is impor tant for him to include in his planning the fact that some fish will die.
This i' an extremely important fact for the first-time fish grower to
understand. It is very natural for some fish, the weaker fish, to die in
ponds. As long as fish are protected in ponds and are well taken care of,
fewer fish will die in ponds than would die in natural waters. But a
farmer who does not expect some death may get discouraged and give up
before he has given his pond a chance to work. It is never too early to
introduce this idea.
KINDS OF FISH FARM OPERATION In nature, many fish never reach adult size because they are eaten by other animals (predators), or they
die from disease or lack of oxygen. In fish culture, the farmer tries
to control the pond situation in order to produce more fish. In ponds,
predators and so on can be controlled so that the pond yields more fish
per hectare than do natural waters.
There are two major kinds of fish farms -- those which breed fish and
raise the fry, and those which rear fry and fingerlings (the young fish)
to market size. So the farmer, after finding possible sites, etc., most
decide if he is going to breed his fish and raise the fry. Or if he is
going to buy fry and fingerlings and rear them to market size, not
getting involved in breeding.
Breeding fish requires more time and more ponds than simply rearing
fingerlings. And building more ponds can be more expensive and requlire
more ongoing management. So the farmer must finally determine his reason
for raising fish: to eat; to sell; to use his land better; or all of
these. He will have to have all these things firmly in mind so that he
can:
build the right kinds of pond.
build the right number of ponds.
stock the right kinds of fish.
TYPES OF PONDS The types of pond a farmer can build depend on water
supply, soil, and topography, the factors which were just discussed. The
two types of pond most often built are barrage ponds and diversion ponds.
Many aspects of the construction of these ponds are the same. The main
difference between these two types of pond is the water source.
Barrage Ponds. These ponds are usually filled by rainfall or by spring
water. A spring, for example, sends water flowing through a small valley
or down a slope into a low place. Or a spring bubbles from the ground
into a natural depression. The pond is formed by collecting water at the
base of the valley and in the low places. The farmer does this by build ing a wall (dam) which holds the water inside what now is the pond area.
The wall keeps the water from entering and leaving except as needed.
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,'".
..
"
,SE1UES
OFBARRAGE PONDS
DRAINA E PIPES
The number of pond walls the farmer must construct depends upon the land
and on how he fixes his drainage system. A barrage pond usually needs
only one wall -- the main wall between the water source and the pond area.
One kind of drainage system called a sluice (see "Construction" section)
can be used to let water both in and out of the pond. There are also a
number of simple drainage systems which can be used that do not require
any complicated construction.
Barrage ponds should not be built where the flow of water is too great:
it is difficult to keep the water from breaking down the wall if the
pressure of the water is too great. Brooks and streams which flow well,
but not too strongly, make good sources for barrage ponds.
Even when the flow of water is not great, however, barrage ponds require
overflow channels. Because barrage ponds are usually built in low areas,
they are likely to fill uo in heav rains. Overflow channels are any
kind of system which can be set up to stop the pond from collecting too
much water. The overflow takes extra water away from the pond. If this
extra water is not taken out, the pond wall may break. Therefore, the
overflow system is needed to help the drainage system handle the flow of
Water when there is too much water in the pond.
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The overflow system can be wide grooves cut into the top of the wall
toward the ends away from the middle; it can be large hollow tree trunks
which are set into the tops of the wall and work as pipes to drain the
water into ditches, or even to carry the water into storage areas for use
later when the water supply islow. Another kind of overflow can be
ditches, dug into the ground above pond level, which take the extra water
away when the water rises to that level.
An overflow often isnot screened, because if something large catches
on it,the pressure of the water behind Itmight cause the entire wall to
break. This fact results ina loss of fish at time of flooding.
OVERFLOW
DITC \_ ,. .
.......
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...
3 SCREEN
WATER
DRAMGE
D)TCH
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iW
w2/0
DRAIN
-
ATE R
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SCREEN
22
Diversion ponds can be made in a number of ways. Sometimes a pond is dug in flat ground or can be made by slightly enlarging a natural depres sion in the land. These ponds, like the barrage ponds, require walls depending upon the
topography of the land, the drainage system used, etc. A pond dug in
flat ground often requires four walls; a pond built in a natural depres sion may not.
With a diversion pond, the water is always brought to the pond instead
of running directly into the pond. Water can be diverted in a number
of ways. For example, a small stream which gets its water from a larger
stream nearby can be danned and used as a diversion channel to feed a
pond. Or water can be diverted to a pond from an irrigation ditch which
carries water to agricultural crops from a nearby well or lake.
A farmer may have one diversion pond, or if his space allows and the
water supply is sufficient, he may have several. When a series of di version ponds is built, they are built in one of two ways:
RohOay Aytem. These ponds are built one after another in a
string. In this system, all the ponds drain into each other
and must be managed as if they were one pond. Therefore, if
the first pond in the series (the pond with the water inlet)
is full of predators which must be poisoned, all the other
ponds in the system have to be harvested (have the fish taken
out) and drained before the first pond can be poisoned and
drained.
\ "- _--
"
illDIVERSION
DRAINAGE
j-URE
fPtao zy~tem. In this series, each pond has its own inlet
Uet and outlet. Therefore, each pond can be managed as a separate
pond.
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24
ponds depends on the fish species being cultured. In fact, eggs and fry
can even be kept in washtubs, oil drums or any other such container which
holds enough water for the number of fry and is supplied with enough
oxygen.
:I
bigger than nursery ponds, and brood ponds are bigger than rearing ponds.
Sometimes a farmer will have to choose between one large pond or several
smaller ponds. His site would allow him to decide either way.
Here are some advantages of small and large ponds:
Smatt Ponda: harvest easily and quickly
drain and refill quickly
treat for disease easily
are not eroded by wind easily
Lae Ponds: cost less to build per hectare of water
take up less space per hectare of water
25
26
pond is harvested (the fish are taken out). The pond area can then be
prepired for a new batch of fish and stocked again.
One pond can provide a good food source for the family. However, rearing
fish means that somewhere there must be a source of fry or fingerlings
for use inthe pond. The farmer must check his area carefully, so that
he issure the young fish are available befkre he builds one pond.
The source can be a river where he collects the young fish, or a local
fish farm which breeds fish to supply farmers who have small ponds, or a
government hatchery where the farmer can buy the young fish. If the
farmer decides that he wants to breed fish in his pond, it Is possible
to breed some fish inside small nets placed in the pond. A single pond,
though, isusually used just for rearing fry or fingerlings to a good
size for food and market.
While one pond usually means that the farmer iswise raising one batch of fish from fry or fingerlings to still must decide what kind or kinds of fish he will He can raise one kind of fish alone (monoculture),or several kinds together (polyculture).
to concentrate on
market size, he
raise In his pond.
he can raise
MONOCULTURE Monoculture is the culture of only one species (kind) of fish ina pond. Itcan be tilapia of one species, common carp, or any
other single fish species.
Monoculture has some advantages. One advantage is in intensive fish
culture practices, where fish are fed a lot of supplementary foods for fast growth. Itis easier to give these foods If there isonly one type
of fish inthe pond. Another possible advantage is that monoculture
gives greater control over the age and sex of the fish. Inmonocultures,
fish can be of all different ages and life stages, or they can be
separated into fry, fingerlings or brood stock.
27
e-,
--
MIXED AGES
SEPARATED BY A^0
Ifone
4
o
time.
In monoculture ponds, fish are harves ted selectively by using nets which
have meshes of different sizes. For
example, ifthe farmer wishes to
harvest larger fish for market or breeding, the net will not catch or
hurt the fry or fingerlings, because they are too small to be caught by
a large-mesh gill net. This allows
the farmer to keep his pond in
operation and producing fish for food all year.
-:
*
-d<
5ELECTIVE
HAVSI'IN
28
29
..- '.o : :
N/EAD
-IR
KO
Poputatio
30
A 6dAme4rmuat be
=utto avoiZd
the ptobtem o6
31
rhere are no crosses that produce 100% female offspring as yet. Males
.re preferred because they continue to grow during the breeding season,
when there are no females present -- even though they (the males) contint
to build their nests Inpreparation for mating.
Monosex culture isa valuable method of pond culture, but isusually
difficult to do: the hybrid crosses are very new; hand-sorting fish by
sex causes many of the fish to die from stress. Even if the fish are
sorted without stressing them, one fish of the opposite sex that
accidentally finds its way into the pond can ruin the whole monosex
culture. So monosex culture is generally not practiced by small-scale
fish farmers.
THE MORE-THAN-ONE-POND OPERATION A farmer who has a larger area to work with might wish to consider having two or three small ponds. Perhaps two ponds would be diversion ponds, and the third, a barrage pond fed by a spring. Perhaps the farmer has room for only two barrage ponds. He does not want to keep eggs and fry inthe ponds because it is harder to protect eggs and fry in barrage ponds. This does not mean he cannot breed fish. He can keep eggs and fry inan oil drum, washtub, or anything else.as long as the water is clean and contains plenty of oxygen. With three ponds, one pond can be the rearing pond inwhich fingerlings
are raised to market size; one can be used to keep brood stock; and the
third, and perhaps the smallest, can be used as a nursery pond where the
eggs hatch and the fry grow to fingerling size. If the farmer does not
plan to breed fish, then he can use all three ponds as rearing pends.
He should not do this, however, without thinking ahead to the harvest
and making plans for marketing the fish he will grow, or preserving the
fish for sale or use later.
32
The major difference between a large farm operation and a small one my
be only the number of ponds. Three ponds isenough to have a full-fledged
operating fish farm which includes breeding, selling fry and fingerlings
to other farmers, and raising fry and fingerlings to market and brood
size. Once the farmer is a skilled pond manager, these ponds should do
well and provide a good return on his investment.
Until the farmer iseAperienced, however, it is better for him with small efforts and a smaller operation. Small pond failure to start
is not as
severe. Once the ponds are working well, the farmer can expand and build
more and/or larger ponds. But he should be encouraged to start small.
There are a lot of factors infish pond management that are learned best
by experience. But a bad experience will discourage, rather than encourage,
the pond owner.
A FINAL WORD ON PLANNING PONDS Good planning is a nust for a successful fish pond operation. Itis during the planning process,
before any money or a lot of time and energy is spent, that many problems
can be solved.
The farmer should keep inmind while planning that ponds do not have to
have expensive equipment in order to work well.
Far more important than
the equipment are 1) an understanding of the general principles involved,
2) the selection of a tish or fishes that will do well inhis pond (see next section, "Selection of Fish"), and 3) good daily management of the pond (see section 6, "Managing the Pond").
33
The farmer now has a firm idea of his site and the types of ponds it is
possible for him to build. He also should know what he wants to do with
his ponds -- raise fish for food or run a fish-marketing business. Now
he must consider very carefully what type or types of fish he is going
to raise in his ponds. The success of the pond depends upon choosing
the fish that will grow best in the type of ponds and conditions that a
farmer is planning.
The following pages give some: 1) general information on characteristics
of fish, and 2) detail about certain fish which have proved to be good
pond fish and why. This information should serve as a guide to -afarmer
trying to decide which fish will do best in his ponds.
Characteristics of Fish
The major body parts of all fish perform the same functions, and they
are located in about the same places on any different fish's body. But
the size, shape, and color are often different, and these differences
help tell the fish apart. Knowing how a healthy fish looks is important.
All fish have a tail consisting of the caudaZ peduncte and the caudat
6in. The fish's fins help it steer through the water and hold it
upright in the water. Often a sick fish cannot steer or flops over on
its side. Other fins on the body include:
Pearto -- usually located on the sides of the fish behind
the head.
Petuvi -- usually located towards the rear of the body where
the hips would be if the fish were a four-legged animal.
o zat-- runs along the top of the fish. May be single or
double. The second dorsal fin is sometimes called the uot joc4aZ
6i.
34
DORSAL FiN
EYE
NOSTRIL, MOUTH
OPERCLLL PELVIC
ADAL FiN I ANAL VENT PECTORAL FiN CALLDAL PEDUNCLE ANAL FiN
35
Some fish, like catfish, also have boAbet , small projections that hang down from the sides of the mouth. Barbels help the catfish sense Its
BARBELS
When a farmer breeds fish he will want to be able to tell the difference
between male and female fish. This can be difficult with some fish.
However, some fish change color in the breeding season (tilapia, for
example), so they are easy to identify by sex. Some fish can be classi fied according to the color and size of their genitals. The separation
of fish by sex is best learned by actual experience in the pond.
AHUS
M~ALE N S
TA'IL
HEAD
FEMALE
UuT
GENITAL PAPi LLA URETER,
36
When the farmer goes to buy fish, he must already know what healthy fish
look like.
It is very important that he be as familiar as possible with
each of the fish he decides to raise.
He must know the of that fish and its life cycle, Its eating and breeding characteristics
habits, etc.
The farmer who begins any fish pond enterprise without having this kind
of information is inviting failure.
And if it is a new venture, it is
particularly important that the farmer's first effort be as successful
as possible.
37
As the fry grow bigger, they are called fingerlings. They are called
fingerlings because at this stage of the growth cycle, they are about the
size of a person's finger. Fingerlings vary in size -- from 4-10cm.
Above 10cm, the fish is better called a post-fingerling. The adult fish
ranges in size; some can be as large as 2m long and weigh 22kg. An adult
fish is a fish which is sexually mature.
Fingerlings have different eating habits from fry; they are now much
bigger and can eat larger pieces of food. As fingerlings, the fish begin
to show that they like certain foods better than other foods. Each kind
of fish chooses its own kind of food, depending upon his needs and what
is available. For example, a carp fry will eat plankton; as a fingerling,
the carp eats pieces of decayed matter and insect larvae; as an adult
the carp will eat plankton, decaycd matter, insect larvae, worms, snails,
and almost anything that is on the bottom of the pond. Common carp, for
example, are called "bottom feeders," because they eat food from the bot tom of the pond. The food preference does not always change as the fish grows. Some fish, like the silver carp, eat plankton their whole lives. When the fish reach adult size, they will sexually mature in the right conditions. Brood fish are sexually mature fish which are chosen as good fish to breed (spawn), produce eggs and begin the whole cycle again. This is called the life cycle of a fish. Knowing how the fish in the pond grow, and the foods they require at each stage in the life cycleis very important for good pond management. MiCAoCopiC ptankton
38
There are many fish that do grow well in ponds. Some of these are fish,
grown locally;
some are fish grown in other parts of the world.
Many governments today are introducing exotic fish species (these are
kinds of fish not native to that country) into fish pond programs.
They do this for three reasons:
Some introduced fish grow better and faster than native fish.
Some introduced fish are preferred by people for eating (over
local fish).
The offspring of a cross
between a local fish and fish sometimes grow faster and taste better than an introduced
either of the
parent fish (this is called hyMid Ugoio).
But exotic fish must be watched and used very carefully. They must not
escape into local waters.
Some exotic fish which in natural waters when they begin to compete with escape create problems
local Also, introduced fish can carry diseases or parasites
fishes for food.
that are fatal to
native fishes.
There are certainly a number of fish in the natural
area which will grow well
in ponds. Native (local) waterways of your
fish are usually
easier to use because they are adjusted to
local water and climate
conditions.
If at all possible, farmers should be encouraged to using a tested pond fish which is locally available start their ponds
and is well-liked
by people in the area.
It can be a fish from the list given here or
one chosen from a list prepared in your area.
The important points
are that the farmer be able to sell
any fish he wishes to sell, that
the fish can grow in ponds, and that there is brood stock available
locally.
39
4. Cau4aiia awu~tu 5. CA
caA,&i6uz uA
9. CLAkt
40
NAMES (Continued) Genus - species 13. Cyp'u c4pio Common name common carp
kissing gourami
silver carp
rohu
mullet
black carp gourami
20. 0phkonemnw goiwn 21. 22. 23. 24. SeAt nochi.omia AobutuA TZiap a mrohik TiJap& meLanoptewi TJiapiZ a mozaambZ
25. Titap.a nitotZw 26. 27. T'UchoguteA pecto atia T~ihogteA ttthdptvuh
The common carp, Cyp., caApio, is a favorite warm water pond fish. Common carp are used as a pond fish because they: * spawn easily inponds.
41
Common carp generally are a grey-green color. However, they also can be
gold, yellow, orange, pink, blue, green, or grey. They spawn all year
round inwarm waters, and they can be made to spawn by the pond owner.if
they do not spawn naturally. Common carp are good to eat when they are
cooked properly. They can be grown inponds by themselves (monoculture)
or in ponds with Chinese or Indian carp (polyculture).
Some of the yields gotten invarious countries by stocking common carp in
monocultures are shown in the following table.
Yield, kg/hectare Culture methods Country Czechoslovakia Guatemala India Indonesia Japan Nigeria Philippines United States Growth in ponds with ducks Intensive culture inponds Natural growth in ponds Growth in ponds with management Intensive culture inponds Intensive culture in ponds Commercial culture with fertilization and feeding Intensive culture instagnant water Intensive pond culture with i inorganic fertilization Ba4dac, 500 4,000 400 1,500 1,500 5,000 371-1,834 5,500 314
Sou.ge;
et at (1912)
42
Ti&ia moa4mb.c
Tilapla are herbivorous: some species eat higher plants; phytoplankton.
Both the Java tilapia and the Nile tilapit some eat
nitotica) do well invery enriched waters (waters pollutp, (T.UAp&z
by All tilapia have slightly different eating habits, depening sewage).
on the
species.
Tilapia reproduce every month or so, once they become sexually mature.
They then take very good care of their own eggs and fry in ponds. If
the farmer plans to breed and raise fry, this fish isa good
because the fish themselves take care of the fry at a stage choice
fish of other species die easily.
The major problem with where many
raising tilapia
In fish ponds is that they become sexually mature at a small size, and
43
CH1IWESE CARPS
Other kinds of carp, besides the common carp, often are grown in ponds.
Most commonly used are the Chinese carps. Some of these are:
44
II 4,500
-
IV
9,000
3,000
200
12,200
200
5,300 (1972)
45
The preceding table shows polyculture mixes: as you can see, common carp
can also be used in pelyculture with Chinese carp. Chinese carp are
grown in ponds because they grow well in polycultures, and they are very
good to eat. The silver carp grows faster and is tastier (according to
some farmers) than common carp. The grass carp is most often used to
control weeds in the pond. In fact the grass carp does a better job of
weed control than do chemicals. The grass carp is perhaps the most inter esting of the Chinese carp and Is now being studied by scientists in
many countries to find better ways of breeding it in ponds.
A farmer might run into problems raising ChineFe carp -- if he does not
look into his local situation very well. Farmers will have to have a
source of Chinese carp fry from a government hatchery or a local breeder
before trying to raise Chinese carp. The carp only breed once a year,
and then, in most cases, only with help from man. Also, Chinese carp are
very susceptible to diseases. Then, because they are delicate fish, they
must be handled very carefully, or they will be injured.
Conclusion: A farmer just beginning a fish pond probably would not want
to breed Chinese carp, but he certainly should be familiar with these
fish and how they might help his ponds. For example, even two or three
large grass carps placed in a pond with many fish of one other species
could be valuable for keeping a pond balanced.
INDIAN CARP
There is one last group of carp often cultured in ponds. These are the
Indian carp. Indian carp are further divided into minor and major carp. The major carp of India are the catla (Catta cat t), the rohu (Labec IoLt),
~ .- ~gE i
46
and the mrigal (CWAhim m4o a). The minor carp are the reba, the bata, the sandkohl, and the nagendram fish. The Indian major carp will not spawn in standing water, so special ponds are built in India to provide
a flow of water for these fish, who must have running water in which to
spawn. The Indian carp can be made to spawn by man, but this is a dif
ficult process (see "Manacling Broid Stock"). However, there seems to be
no reason why the Indian carp cannt be spawned in ponds in places where
ponds can be constructed to provide constantly running water.
Conclusion: A farmer who has only a small pond should not try to breed
Indian carp. Indian carp can be grrwn in polycultures with common carp,
but are not as good or fast growing in ponds as the Chinese carp.
Indian carp are also susceptible to many diseases. This is a fish for
an experienced fish farmer who is interested in, and able to, experiment.
GOURAMI
The gourami (Ophvtonemz. gozumy) is a very good pond fish. It is originally from Indonesia, but now is grown all over Southeast Asia.
Gourami possess an accessory air-breathing organ, which means that they
can survive in waters that are low in dissolved oxygen. This makes it
an important fish in areas where the temperature remains high and there
is little water for certain periods of the year. Gourami spawn all year
round in warm water conditions. Gourami:
spawn easily all year round in warm waters.
taste good.
are easy to breed.
accept a variety of foods.
are hardy.
47
Conclusion: Gourami are good fish for a first-time fish frmer. And
they are certainly a fish to be considered very thoughtfully by farmers
who live inareas that remain very hot and dry for periods of the year.
The gourami isused to these conditions, and there are other pond fish
which would not do well at all under these conditions.
CLARIAS CATFISH
CeaAias catfish are found throughout Asia, India, and Africa, as well as
the Middle East. The species most often used as pond fish are Ctwtiah
macwocephatuz and CtaU" batwchuh. CtarJa macoephatu is preferred for its good taste; CUa.i" bat aeu6 grows faster.
These catfish have acLessory air-breathing organs; they can even crawl
out of ponds to look for food. Because they can live in shallow ponds,
these catfish are sometimes used inculture with rice (see paddy culture).
They are scavengers, which means they will eat just about anything.
However, they prefer to eat worms, snails, and other fish.
They are
often used in polycultures with tilapia where they serve as predators on
the very small tilapia. They will eat supplementary foods, and give very
high production in ponds. InThailand, Ctatiaz catfish yield about 97,000kg/ha when they are fed supplementary foods. These catfish are hardy: they sometimes get external parasites, but these do not kill the fish.
Conclusion: The catfish are another good fish to be raised inareas
where high heat and long dry spells are found. They are good to eat.
easy to keep, and can be used in ponds ina number of ways. Certainly
a farmer who already cultures paddy rice might be interested inconsi dering adapting his paddy to catfish culture.
TAWES
48
Conclusion: There is not yet a great deal known about the Heoteiotz nitotidu4 as a pund fish. But it seems that it is a good choice of fish
for warm climates and warm waters.
A farmer who lives in such a climate
might find raising, and even breeding, this fish quite easy -- particu larly in a very well-fertilized pond.
49
OTHER GOURAMIS These are the snakeskin gourami (or Sepat Siam -- Th4chogazt't pectoatwAa), the three-spot gourami (Tkchogazte' ti.hoptetuA), and the k.ssing gourami (lfletotoma temn kic All of these fish taste good. And they ). breed easily in well-oxygenated, warm water. They do require a pond which has a good growth of vegetation (particularly Hyd'ti veiL eWata).
50
Ewwopean eet
OTHER POND FISH Some other fish grown in ponds are the goldfish (Ca iuA auAMatw), the
crucian carp (CaAo.u4zaaA suzA), and SeitzunocdWmi4 Aobuaaa. c Any of
these fish can be grown in polycultures with Chinese, common carp, and
tilapia.
Conclusion:
The use of one of these fish in a pond stocked with other,
more important fishes, results in an increase inyields of both species.
In polycultures these species can otilize other food sources and also
act as predators and weed controllers.
51
r tC
Lampoan 6.Zam
Lampan java
One other fish species used in freshwater ponds isthe striped mullet
(MugZt cepatu.6). Like the milkfish, the mullet isprimarily a salt water fish, and its fry are collected as they swim upstream. Recently the mullet has been made to spawn by man, but this is difficult to do because mullet are very sensitive to handling. However, mullet can survive in wide temperature ranges and are herbivores, so some farmers may want to try mullet.
All these fish have been and are now being cultured in fish ponds around
the world. However, as stated before, they are not the only fish which
can be growr inponds. Inevery area there are a number of fish in
natural waters that could be qrown in fish ponds. So you might find it
52
a good idea to experiment with local fish in your ponds, to find those
fishes that might be available to farmers in your area for use in their
ponds. It is better for an extension worker to do the experimenting
than it is to have a farmer risk wasting his time or money, or even more
importantly, risk failure. If a farmer fails, he may not want to try
again.
54
" '
WALLS
"RAINA&E
SYSTEM
A fish pond has three main parts: the walls, the water inlet, and the
drainage system.
Walls are also called dams, dikes, levees, or bunds.
This manual uses "walls." Whatever they are called, walls hold the water
in the pond.
They can be built using soil taken from inside the pond,
or they can be built with soil taken from another place. They must be
strong enough to withstand the pressure of all the water inside the pond:
water constantly pushes against the walls.
They must also be water
tight (impermeable), so the pond does not leak.
55
The water inlet, located above the pond water level,
is used to let water
into the pond and is closed off after the pond is filled.
The drainage system is used to empty the water from the pond when the
farmer is ready to harvest the fish.
There are many ways of making inlet and drainage systems: the most
important criterion is that they work.
But the walls are especially
important: they are all that keep the fish inside the pond.
The walls
must be built carefully.
Pond construction follows the same principles whether the pond isa
single backyard pond or part of a large fish hatchery. These are the
steps in pond construction:
Survey the land
Mark out the area of the pond
Measure and mark out the walls
Excavate the pond bottom, if necessary
Build the drainage system
Build the water inlet
Build the walls
Seal the pond bottom and wails
Each of these steps will be discussed in detail in the following pages.
56 There are a number of ways which can be used to determine slope. Th3
w:ay outlined here probably would not be used by many farmers If they
were building a pond on their own, but this is an accurate method of
determining slope and should be encouraged if at all possible.
STAKE
To survey the laad for slope, some stakes (long, straight pieces of
wood), some string (fishline, etc.),
and a carpenter's level are needed.
Most farmers will not be familiar
with the level, a device that has
an air bubble trapped inside which
rests between two drawn lines.
When the level is placed on the
ground, it shows whether the area
is flat or sloped: if it is straight
or flat (level), the bubble stays
STRIN&
K<'~.
a4pejvteA14 teveL
57
<ooc-
.1
GRO LEVEL
This drawing shows that one string is tied at 20cm; the other is tieJ at
25cm. Therefore, one end of the area Is 5cm lower than the other.
ihe
distance covered by the string is 100cm, so the slope is 5% (over 10(0cm
of ground, the elevation changed 5cm). Since a slope of 2-5% is good for
a fish pond, this site has a satisfactory slope for a pond.
Other Ways of Determining Slope. As mentioned earlier, the above method
of measuring slope Is a good one, but it may be difficult for some people
to do. It is possible to calculate slope roughly. A farmer, who realizes
that what he is looking for is a way to place his pond so that the water
can enter from the water source and drain away well, can figure the slope
of his land by doing such things as rolling a ball or other round object
and watching carefully to note where and how quickly the ball rolls. A
good slope would mean a slow-rolling ball. A variation of this involves
throwing a quantity of water, or a mixture of water and dye on the ground
and watching the path it takes and its speed as it moves along the ground.
It is important to consider slope carefully. A well-placed pond with
good drainage is easier to care for and has more chance to be successful.
It may be necessary for the pond owner to measure his land only once to
find a good location. Or it may be necessary to repeat the measuring a
number of times. This is probably a good thing to encourage since
locations which look alike to the eye often have enough difference in
slope to make a big difference to a fish pond. Also, determining slope
58
is a larger project if more than one pond is being built. Then the ponds
must be laid out in relation to each other.
There may be several areas which have the correct slope, but only one
which is good in terms of getting the water into the pond from the water
source and out of the pond easily. For example, the farmer might like
to drain his pond so that the water irrigates his fields. Therefore, he
will want to keep this in mind when he decides upon the exact placement
of his pond. Likewise, if he is building a pond on a hillside in back
of his house, the slope may be perfect, but he will need to avoid drainage
into his build gs.
Once the slope is found, the location of the main wall can be determined.
Of course, if the pond is built on flat ground, it will have four walls.
If the pond is a barrage pond, it may only have one wall. The number of
walls depends upon the land. The shape of the land may mean that one
wall or two walls or four walls will be needed.
Now that the slope is known, the place of the main wall is known. The
main wall is at the end of the pond which-will be deepest, and is the
wall where the drainage system will go.
Mark out the main wall, and any other walls that will be built, with
stakes. The walls, when finished, will be wide: it does not matter so
much where the stakes are placed within the width of the planned walls,
for they are to be used as height markers.
STAKTES
59
The farmer has to plan the depth of his pond and the height of his wall.
If the pond is going to be 2m deep at the deepest end, for example, the
walls should always be at least 30cm higher than the water level for a
small pond, and at least 50cm higher for a large pond. Also, the walls
will settle after they are finished, so it is best to make the wall 10%
higher than the desired final height of the wall. A 2m deep pond, there fore, would have walls with a total height at the deepest point of 2.5 or
2.6m [height of wall before it settles = depth of pond + 30cm (for small
pond) or 50cm (for large pond) + 10% of depth and 30 or 50cm].
Tie strings to the stakes along the main wall line, at a height of 2.5
or 2.6m for a pond whose deepest end will be 2m. Use a levelling device
to connect strings to the stakes marking the other walls, if the pond has
other walls, at the same level as the string marking the height of the
main wall. The strings are the building markers. When the walls reach
the strings, they are the right height.
100 C'"
The pond bottom must be clear of rocks, roots, trees, and stumps so that
later, when a net is used to harvest the fish, the net will not get caught
and tear. If the pond bottom is already smooth and slopes well, it can
be left alone. Or, if the pond bottom only has grass on it, the grass
does not need to be removed before the pond is filled. In fact, once
water is added to the pond, the grass will die and rot and add nutrients
to the water.
If the pond bottom does not already slope downward, excavate (dig out)
the bottom area of the pond until a good slope for drainage is made.
Adjust the height of the strings tied to the wall markers if digging the
bottom has changed the height.
Keep the soil which was dug out of the pond: when the pond walls are
finished, the soil can be placed on top and planted with grass. This
fertile topsoil will root grass easily; this grass will help keep the
walls from eroding (washing away).
60
The pond bottom can be excavated by hand
or by using machines, like bulldozers,
if they are available. Remember: if the
land for the pond is chosen well with regard
to the natural topography, only a small
part of the pond bottom will need to be
dug out. The most important thing is
to have the pond bottom slope so that
OVERFLOW
/
-
SCREEN
DiKE
DIKE L
BAMBOO DRAIN
MULD PLUGr
61
One of the easiest ways to drain the pond is to place a bamboo or plastic
pipe through the base of the wall into the middle of the pond. The end
of the pipe which is inside the pond has a screen over it to keep fish
from entering the pipe. The other end of the pipe, the end that is
outside the pond, isplugged with wood or clay. To drain the pond at
harvest time, the plug is pulled out.
Two other methods of draining the pond which work but are not used as
often, are the siphon and the pump. A siphon is merely a flexible
plastic or rubber tube. One end of the tube is in the pond near the
bottom; the other end is placed on the ground outside the pond. A
vacuum is produced in the pipe by sucking at the end outside the pond
until water begins to flow out. The end of the pipe inside the pond
must be kept in the water or the siphon will not work.
WALWALL
PV40 bOTTOMA
L.CWr-L -M"INLET)
The pump is usually not a good idea for a fanner because the engines
that are used to run the pumps are costly and often not available, or
gasoline to run them iscostly, or they must be given frequent attention
so they will not break down.
All ponds must be drained for harvesting fish. Also, it is a good idea
to let a pond dry out completely once every year or so to get rid of any
unwanted fish and/or disease-causing organisms.
The following are some tested, effective drainage systems a farmer can
consider for his pond.
RIVALDI VALVE This valve was named after a farmer in Paraguay who
first used the system. It is an easy and good method to use in a small
fish pond. A farmer who is building only one small pond for family use
would find this valve a good choice for his needs.
The Rivaldi valve is a flexible plastic pipe. Place the pipe on the
ground before the wall is built. Build the wall. Then turn up and tie
the pipe to a stake. Tie the pipe end at a level which is somewhat above
the usual level of the water in the pond. Keep the pipe up and tied to
the stake until it is time to drain the pond. Then, untie the pipe ard
let it lay on the floor of the pond until the water is out of the pond.
At other times, the pipe works as an overflow to let out water after a
heavy rain: when the water level in the pond reaches the top of the pipe,
62 water will flow down the pipe and out of the pond.
The Rivaldi valve should have a screen over the end inside the pond to
keep fish from going out of the pond while the pond is bding emptied or
drained.
PLASTC PiPE
BOTO
RAI M
SCREEN
WALL
WALL ~ CONCRETE ;u
PIETAL Pi PE
METAL PiPE
PODBOTTOM
-ANCHOR
BLOCK
BOTTOM - WATER OVERFLOW This drain takes water bottom of the pond where oxygen levels are the lowest. directly from the and elbow joint do this also, but each of these requiresThe Rivaldi valve
that the pipe
be lowered
the pond can be drained. The bottom-water so overflow regu lates the depth of water without any need for moving the new water is added to the pond, the less-oxygenated water pipes.
When
at the bottom
drains out automatically.
This type of drain is relatively complicated and usually difficult t
build.
For a small fish farm operation, it would probably not be worth
the effort.
63
OUTER SLEEVE
, BOTTOM INTAKE DRAN WALL
_ ..
CONCRETE
_OLLAR
Bottom-wateA
oL'e~ctfW
DOUBLE SLEEVE OVERFLOW This drainage system is built like the turn-down pipe, except a large pipe is placed over the section of pipe which extends above the pond's surface. This outer pipe should be longer and wider than the inner pipe, which is placed so that it is about equal in height to the depth of water desired in the pond. When fresh water is required in the pond quickly because the water Is
too warm for the fish or because the oxygen levels are low, all the
farmer has to do is to add water to the pond. The double-sleeve overflow
automatically drains the stale water from the bottom of the pond.
,e OUTER
-TLRN-DOWN
-------------------
64
SLUICE A sluice can function in a number of in a pond. It can a screened gate ina water channel going into ways pond, or a drainage
be
the gate leading water out of the pond.
Ina pond, a drainage sluice gate is anchored into the main wall by
extending the sides of the sluice into the wall so the sluice structure
stands upright. The sluice isconstructed at the center of the main wall
before the dike isbuilt.
SLUiCE
The sluice can be made of wood, cement, or brick. It can have one or two
wooden gates
which are removed to empty or fill
the pond. A sluice also
can have a screen gate to keep unwanted fish from entering at an inlet
and pond fish from leaving at the outlet.
W A L L
KEY "///
BRiCK WALLS
EWOO-
APSLU FiLL
//
//iY/ ///p //
_WOOD
5LUiCE GATE
~~CONCRETE
ME3F
65
IMPORTANT: The wooden gates of the sluice must fit into the slots well,
but easily. The wood will swell to make a tighter seal as it is soaked
by the water in the pond. The slots (grooves) can be filled with several
strong, long, narrow boards which have been bevelled or notched so that
they fit together tightly. Or the slots can be filled with single pieces
of wood. When single pieces of wood (or a number of boards which have
been fastened tightly together) are used in a sluice, the pond is drained
and the water flow regulated by lifting the entire wooden structure out
of the groove to a height which allows some or a lot of water to flow out
of the pond. When separate boards are used in the grooves, the boards
are taken out one at a time. If a small flow out of the pond is desired,
only one board may be taken out. To drain the pond, all the boards are
removed. In a sluice having two wooden gates, the space between the gates
can be packed tightly with earth. This will help seal the water into
the pond.
WATER LEVELWODBA WOOD BOARDS S 7"
J
EARTH FILL
DIKE
=CONCRETE
BASE
MONK The monk is very much like the sluice, but it is not built into
the pond wall the way the sluice is. Sometimes the back of the monk
does touch the wall, but it is not built into the wall. Also, a monk is
never used at the inlet as a sluice can be.
0 XD .
iP LL
66
SCREE N
A monk-type drainage system controls the level from escaping when the pond is being filled.
of water and prevents fish
drainage of the pond.
The completed structure Italso allows for good
consists of a horizontal
drainage pipe and the vertical structure, or monk. The drainage pipe
must be placed before the walls are built; the monk may be built outside
the pond, and placed inside later.
The drainage pipe runs from the back of the monk under the pond wall.
Itshould be between 20 and 40cm indiameter; isnot available, two pipes may be used.
For ifpiping of this diameter
pipes 30 to 40cm lower than the pond bottom. good drainage, place the
Make ison solid ground so that the pipes do not bend.
sure the drainage pipe
Bent pipes are difficult
to clean out when clogged.
The monk itself is a structure which isclosed inthe front. The open side should face the on three sides and open
be at least 30cm wide; the entire monk should inside of the pond and should
be at least 40cm above the
surface of the water.
The two parallel sides of the monk, and the bottom, have grooves cut in
them: a monk may have two or three grooves.
One groove, or part of a
groove isalways for the screen. The other groove(s) is for the boards.
Monks-can be made of wood, concrete or brick.
A wooden monk should use
strong wood
- 4 to 5cm thick.
A concrete monk should be reinforced with metal.
poured, a wooden form shaped like the monk ismade Before-the concrete is
and oiled.
A frame,
67
slightly smaller than the wooden form, is made of chicken wire, or some
other strong wire, and set down inside of the wooden form. The concrete
is then poured into the form. A good concrete mixture for monks is
1 part cement, 2 parts clean sand, and 4 parts crushed stone, by volume.
GROOVES FOR BOARDS Cu~aoy o6 monk
BRICK WALLS
DRAIN PiPE
CON
CONCETE ASE06
BATop
vLew
monk
1
Im
5_C__
L [L_
If the monk has three grooves, the first groove can be a large screen.
The screen is what keeps the fish from escaping as the pond drains.
However, if the monk has only two grooves, a smaller screen can be placed
above or below the boards in the first groove. Placing the screen at
the bottom allows water to drain out from the bottom of the pond.
WA-
W T ER A L
OUTFLOW
DRAIN PiPE
There are other ways this kind of monk can be built. For example, tut:
second groove could be filled by a large wooden gate (one piece of wood
or several fastened together) which could be raised and held up to allow
a flow of water from the bottom of the pond. It is this flow of water
from the bottom of the pond which is important.
The Herrguth monk would probably not be used in a pond which is filled
by rainwater. In these ponds -- sky ponds -- a regular monk is used,
and the space between the two wooden gates is packed with mud to make
a watertight seal which lasts for the fish-growing season and is removed
when the pond is drained for harvest.
SOME NOTES ABOUT MONKS Be careful with screens. Bamboo slats
can be used instead of screening if the fish are large. But for fry,
the holes should be less than 2mm in diameter. Often the screens are
made by poking small holes in sheet metal. The screen mesh can get
larger as the fish grow.
A valve is sometimes placed on the drainage pipe behind the upright part
of the monk. This is used to control the draining speed and is easier
to do than to move the boards in'the grooves.
69
A large catching ditch can be made in front of the monk to help with
taking fish out of the pond when the pond is being drained for harvest.
Drainage ditches are channels which should be dug DRAINAGE DITCHES on the bottom of the pond to help the water flow out. Lining the ditches with stones helps the water flow. A small family pond does not require this system of drains. The only real requirement for drainage is a gentle slope.
This is,the time to build other ditches which may be needed. For exam ple, if the farmer wnats to use the wvter from his fish pond to irrigate
his land, he will want to construct the ditches or chann3ls which will
carry the water from the pond to the field or to storage tanks for use
later. Therefore, the farmer must consider carefully where the water
which is draining from a pond is going to go. If the pond is being fully
drained, and the pond is built on flat ground, he should build drainage
ditches around the outside of his pond to drain the water away from the
walls. These ditches should be 30-40cm deep.
DRAINAGE
DITCHES
CATCH
BASIN
MONK,
DRAIV PIPE
Water Inlet
All ponds, except for those filled directly by a spring or by rainwater,
need water inlets. The water inlet must be constructed so that it supplies
adequate quantities and quality of water, and so that it does not allow
unwanted fish or other materials to enter the pond. This usually means
there must be a channel of some kind to bring the water to the pond from
the source and a filter of some kind to keep the water which goes into
the pond clean and free from predators.
71
The horizontal screen at the left Isvery effective. Here the screen Is placed so that the water passes through as itfalls into the pond. This screen merely juts out from the wall at the inlet. In the version below the horizontal screen has a vertical screen wall attached to it. This short wall prevents fish from going over the screen.
/ALL
/1/.
POND
POND
Inany variations of these kinds of filters, the screens should be
assembled into one piece for easy removal as a unit for cleaning.
WATER INLET
A sand and gravel filter is particularly useful for cleaning out fish
and eggs. It requires building a smaller pond or tank at the water
tnlet. If a filter is built in the earth it must be lined with a water
proof liner.
WATER INLET
WATERPROOFLiNER
POND-
73
WATER
INLET
WOOD 50 SARAN
WAALL.-
These filters all have good and bad points. All must be cleaned often
to remove debris that collects in them from the water source. The best
filters are the sand and gravel filter, and the saran filter, but these
are more costly than the others.
The farmer should examine his water source carefully before deciding on
the kind of filter. If the water is very muddy, or has lots of leaves
and grass in it (organic matter), he can use the wire screen. If the
water source is free of organic material, the mesh bag will work because
it is not likely to be torn. If the water contains unwanted fish and
eggs, as well as a lot of organic matter, the saran filter or the sand
and gravel filter is best.
To clean the filters, remove them and clean them with a brush and fresh
water. Or flush the filter with water in the opposite direction of the
normal water flow. This is called backwashing.
IMPORTANT: Filters must be kept clean to be of any use. These filters
should be cleaned each time water is let into the pond.
74
SILTATION TANK
One other structure which should be built at the
water inlet, when necessary, is called a siltation tank.
Silt is the
mud that is suspended (floating)'in water.
Silt can become a problem
when it clogs the gills of the pond fish so they cannot breathe. If
the water source has a lot of mud in built at the inlet to the pond, or at it, a siltation tank should be
the inlet to the first pond, if
it is one of a series.
The siltation tank can simply be a smaller pond.
The water flows into
6,'s ..
and Is kept there until the mud jnd falls out setates on
the bottom.
Then the clear water is :et of the water and
into the fish pond.
Siltation could also be done in a storage
tank madi out of old oil drums,
etc.
The important thing is that semething that the silt has a chance to fall out of be constructed or set up so
the water btfore that water
goes into the pond.
The silt must be removed from the siltation tank or pond every so often.
The silt which is removed should be used in gardens and 71elds: it is
very fertile.
WATER INLE.T
SI PHON
"////l,.
',.
WALL
,l'
S.TA
'1111t,,1111 TANK
/N//"i/10PN
POND
75
SOIL
WW/((i/4,~,
The finished height of the wall should be about 30cm above water for
small ponds and 50cm above water for large ponds. The width of the wall
at the top should be about equal to its height. For a large pond, the
wall is never less than lm wide at the top; most walls are built so that
two people can walk side by side along the top.
Tamp the soil down with a simple tamping tool. Some people use a large
rock or e',en their own weight by Jumping up and down on the soil. The
important thing is that the soil must be packed down very tightly.
One way to build pond walls ir, soil that does not have a lot of clay or
is very sandy is to build a "key." The key is made of clay soil (itcan
be pure clay) and adds strength to the walls. To make a key, dig a trench (or shallow hole) about lIm deep and lm wide in the center of thce places where the walls will be. Then bring clay soil and pack it tightly
into the trench. Also put a thick layer of clay soil on the pond bottom
and pack that down tightly. The clay layer on the bottom and the key
run together as shown. This connection of the bottom and the key helps
prevent leaking. The drainage pipe should be placed in the clay lining.
76
C~YCORE
'/1"1
"tll -j42", 6., '*
IL
il,
.. . . II / I / CLAY OR 13 EDRO CK i
If the farmer has a soil which is a mixture of clay and sand, and he is
not sure it is strong enough, he may still wish to build he can build a key using the same soil used in the wall. a clay key.
Or
This key must
be packed down very tightly.
TAMPED
The type of soil determines the ways in which the pond can be so water does
not leak out (see "Seal the Pond Bottom", next prepared
page).
1/1: , ,., , :t ,
SAND., SO I
Th' ,ltyp dtines.l~ldl wa.ysl in ofl sil/I the1 wihth pond" ca n' lif/ella bell ... ' L so wate -doesh. dlea u (see "Sea] notIb Pond, BottoI, Ynext. .i'.,ItIIpage"zz.,H II .. /ltlthe --. ....
77
The soil also determines the slope of the walls. Soil with a lot of
clay in it can have a greater slope on the outside wall than on the In side wall. A typical wall is built with an outside slope of 1:1 and an
inside slope of 1:2. A slope of 1:2 means that for every change In
length of 2m there is a change of Im in height.
Once the walls are constructed, the farmer should plant grass on them.
The grass roots help to hold the wall together and prevent erosion of
the soil. However, NEVER plant trees on the wall. As the tree roots
grow they will crack and destroy the wall.
WALL
VIM
\CLAY LINNG.rr
CLAY CORE
A pond can be sealed using hollow cement blocks, but this is expensive.
Another method of sealing the bottom calls for using a sheet liner made
of polyethylene plastic, or a rubber liner. The waterproof sheet is
placed on the pond bottom and around the sides in one piece (the farmer
may have to tigntly seal several sections together), then covered with
soil.
Another technique, recently developed in the USSR, is called a "gley" or
"biological plastic." "Gley" can be made in the pond in this way:
Clear the pond bottom of debris, rocks, and all other materials.
Cover the pond bottom and sides completely with pig dung.
Apply t0e dung in an even layer.
Cover the pig dung layer with banana leaves, cut grasses, or
any vegetable matter. Make sure all the pig dung is covered.
78
79
80
because he had no place to get his soil tested, or because he has never
farmed the land -- is always safer if he puts lime on the bottom of the
pond.
Lime comes in several forms: ground limestone; agricultural lime;
hydrated (builders') lime; or quicklime. Of all these types, hydrated
lime is cheapest to use because it Is more concentrated.
Quicklime must be used carefully: it can burn if it touches the skin
and is harmful if breathed Into the body. Farmers should be warned to
use quicklime only with extreme care.
Lime should be put on the pond bottom at the folleiiing rates for a new
pond: Ground Limestone Agricultural Lime Hydrated Lime Quicklime 1140kg 2270kg 114kg 200kg per per per per hectare hectare hectare hectare
81
The water should not go in too quickly. If the water goes in too fast.
the pond bottom will get stirred up and make the water muddy.
Let the pond sit for a few days after it has been filled. Then check the
quality of the water in the pond -- before adding the fish.
Fish growth depends greatly on the quality of the water used in the pond.
And the quality of the water depends upon where it comes from and what
kind of soil it travels over. Testing the water quality means making
sure that all the factors which relate to water are right for the fish.
These factors are: temperature, oxygen content, pH, turbidity, hardness,
alkalinity,and nutrient availability (source of food for the fish). The
farmer does not need to know these particular words to raise fish well,
but he does require a working knowledge of the factors that are part of
the water world in which the fish live.
TEMPERATURE
Fish are cold-blooded animals; that is, their body temperatures depend
upon the temperature of the water in which they live. Every fish species
has a temperature range within which it grows quickly. This is called
the optimum temperature range, and it means that this fish grows best
at temperatures within that range. In a fish pond, the fish should live
at their optimum to grow well. However, since fish have different
temperature requirements, the farmer must choose the fish which will
grow best in the temperature range of his pond.
Here are some of the common pond fish and their temperature ranges:
Genus, 6pecZ.. Common name TempeatjAe O(C TZapiLa mosarnbica tilapia 25-35 06ph onenus goLamy gourami 24-28 Punti" jauaniZcua tawes 25-33 Cyp,,Unu caipo common carp 20-25 Ctenophatyngodon idelu6 grass carp 25-30 AnguitZ-a japoniea eel 20-28 This chart shows that all the fish on this list could live in water that
is 25% (77*F). The chart also shows that an eel can live and grow well
at 200 C, but that the tilapia and the grass carp will not du well at 20C
because this temperature is below the range in which they are comfortable.
When the temperature goes higher or lower than this optimum, fish will
not grow. Eventually, if the temperature goes too high or too low,
the fish will die.
The farmer must watch the temperature In the pond water carefully,
er cially if the weather becomes unusually hot or cold. If it is
possible, it is a good idea for a farmer to use a thermometer to find
the temperature of his pond water. This can be done by using a
82
thermometer which is used for taking temperatures when people are sick.
The most important step is to guide the farmer to stock fish which will
do well in the normal temperature ranges of his area. Then the tempera ture of the water will not generally be a problem, except in cases of
unusual weather.
Some experienced fish growers can judge the water temperature by putting
their arms in the water. Most people cannot tell temperature this way.
But if the right kind of fish has been chosen for the'pond, the farmer
need only watch the fish to be able to judge the temperature of the pond'
water. If the water is becoming too hot, the fish will not eat and will
move very slowly.
If th3 farmer sees this behavior in his fish pond, he can take out some
of the pond water and put in new, cooler water. Another way of pro tecting the water from getting too hot is to find a way to shade the pond,
so that the sun does not shine directly on the water. The shading should
be temporary because sunlight is important to the success of the pond.
X.\1
7/
,-/. /,
--
',,t<--'
83
The picture on the previous page shows a fish pond being shaded by
palm tree branches stuck into the ground around the edges of the pond.
As soon as the temperature of the water goes down, the branches are
removed.
Temperature, however, usually does not act alone. If the fish are
showing signs of distress because of hot weather; it is often a problem
caused by high temperatures and low oxygen content.
OXYGEN
The farmer cannot see oxygen, so it may be hard for him to realize
its importance. But it is worth taking the time to help a pond owner
understand oxygen as a critical factor In the success of his fish pond.
Oxygen lack is a problem which can occur at any time during fish pond
operation, and there is a good chance the farmer will have to depend
only upon his own knowledge of the problem and its cause to solve it
immediately.
Fish, like all animals and human beings, need oxygen to breathe and,
therefore, to live. Through a process called respiration, fish and
human beings take in oxygen and give off carbon dioxide. Fish will not
grow well when the oxygen supply is low; and if the oxygen level gets
too low, they will die.
Oxygen is a gas. Human beings get the oxygen they need from the air.
They cannot see it, or smell it, but without it they would die. Most
fish can only get oxygen fromte water in the fish pond. The farmer
cannot see the oxygen in the water either, but he should realize that
it must be there in sufficient quantity for the fish to live.
Oxygen troubles arise in a pond when the supply of oxygen is used up
faster than oxygen is put into the pond. This happens to human beings
too -- if too many people are shut into a room with no windows or air holes, the respiration of all these people uses up the o,(ygen. Soon,
there is too much carbon dioxide in the air. The people have trouble
breathing until a window is opened and fresh air containing oxygen is
let in.
This is exactly what happens to fish in the fish pond. The fish are shut
up in the pond, and if there is not enough oxygen entering the pond,
they will have trouble breathing. And, if the problem continues, they
wi!l die.
Water contains tiny plants and animals called plankton. Most plankton
are so very small that they cannot be seen without using a microscope.
et tum u op.1
N'
'Atona
sp.
Water also contains higher orders of vegetation. These plants are much
larger than the phytoplankton.
Azola pnata
The fish and the zooplankton use oxygen and give off carbon dioxide in
respiration; the phytoplankton and higher plants use carbon dioxide and
sunlight to produce oxygen during a process called photosynthesis.
01
1 / \\
1/
.and
85
The new water should be sprayed or bubbled into the pond so that the
water picks up oxygen from the air as it falls into the pond.
Oxygen also can be added to pond water by:
water nir Some farmers beat ~pond. Stirring up the poles.
llalready with ~water lll,
' '
1 '~~~~~~~ nd
I[ l .. ,ll,
\J"
'
p ti'/l
f . 'l"
Il
86
Other owners run small motors to bubble the water in the pond.
<- Z-"
In addition, winds which are strong enough to ripple the surface of the
water in the pond help the air and water to mix.
Remember: any disturbance
of the water made by man or by nature helps put oxygen into (aerates)
the water.
Life under the water Is a new idea to many farmers. it is difficult to understand that the balances which existAnd land sometimes on are also
present in the water.
Oxygen is produced and used both above and below
87
the surface of the water. The fish pond does well only when oxygen
production and oxygen use are in balanced relationship.
If the farmer understands the bdlance-how oxygen is added and how it is used
up, he will know how to watch for trouble
before it happens. For example, if
the color of the water changes from green
to clear-_ ina few hours or a day - the phytoplankton are not producing enough oxygen. If the fish are at the
/
&
CO 0
OC
.1 C0 1. 02LQ.0.
._ CO
CO . C:
COX(07
CC C I.1
the O 1 C 2surface of water and seem to be gulping air, they may need oxy gen. Early in the morning, before A C )Vtheno sunshine or a long period sun comes uo, of can be bad times be cause the phytoplankton need the to produce oxygen. Long periods Of hot weather can create oxygen
-7problems because the pond water gets warmer, and warmn Water cannot
0-YC0
CO 1.sun
88
Time of Day 2 am 6 am
10 am
2 pm 6 pm 10 pm
Temperature *C 29
29 29 30
29
29
___.-
"
--
_-"
89
pH, HARDNESS, AND ALKALINITY These three factors are not the same thing -- each one is a measure of
a certain charact'ristic or characteristics of the water in a fish pond.
Each of these faccors can be measured exactly if semoles of pond water
can be taken to a laboratory to be analyzed, or if chemicals are
available for testing the water in the field. Certainly if such
testing is possible, it should be done.
However, many pond -wners are not able to get their water tested and
they do not have the right chemicals and equipment to do the tests
themselves. For these people, it is best to stress the importance of
using lime in their ponds. Lime is the proper treatment to correct
imbalances in these factors, each of which is discussed in some detail
here.
90
REMEMBER:
THESE THREE FACTORS ARE NOT THE SAME THING, BUT THEY ARE RE-
LATED. IN FISH PONDS, ALL THREE CAN BE CONTROLLED BY ADDING
LIME TO THE WATER.
TURBIDITY
lurbidity is the term for the suspended dirt and other particles in water.
Turbidity can be a problem, especially in shallow ponds, if the dirt and
particles prevent sunlight from reaching the plankton, so that the phyto plankton cannot produce oxvgan. An oGerating pond can be turbid if there
91
are bottom feeders such as common carp stirring up the bottom mud. Or,
turbidity can result from a water source :,1u has a lot of silt in it.
Turbidity can be measured by just looking at t.e pond water. Or turbidity
can be measured by using a device called the Secchi disc. The Secchi
disc is also used to determine thi total productivity of the pond.
A SECCHI DISC
92
Turbidity also can be measured without a disc, but this requires somewhat
more experience. The farmer stands in the pond and sticks his arm under
the water.
\ -_before
--
....
-turbid
-
L __ r-_
_
-.--
...........
If the his hand disappears when water is about elbow deep, the water is not too turbid. If it disappears the water reaches the elbow, the water is either or very productive. If the entire arm from hand to shoulder can be seen under the water, it is not turbid at all, nor is it very pro ductive (itdoes not contain enough fish food).
One way to clear up muddy water is to scatter twelve bales of hay per hec tare around the edges of the pond.
The hay will help to settle the and can then be removed easily from the pond edges. However, do not mud
this method is very hot weather, because the hay will begin to decay
use
very quickly and will begin to use up oxygen in the pond water.
If the
pond water continues to have a lot of silt in it, the farmer should
consider adding a siltation tank (see "Construction").
NUTRIENT AVAILABILITY
All fish require certain elements to grow and reproduce. These essential
elements are:
carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium,
sulfur, calcium, iron, and magnesium. Some other elements called
trace
elements, are needed only in small amounts. If these elements are missing,
or present in too snall quantities, the fish will
not grow well.
93
Fish get these elements from the pond soil, the pond water, and the
food they eat. Some fish ponds lack elements that are necessary to
fish. In these cases, it is necessary to add fertilizers to the water.
Fertilizers are simply materials which contain the missing elements.
The elements most often missing, or in short supply in fish ponds,
are nitrogen (N), phosphorus (P), and potassium (K).
Fertilizers containing these missing elements are added to the fish pond to help the growth of the fish and of the plankton, the fish use for food. Fertilization is discussed in the following paragraphs.
OTASSUV
POSPHORUS
Fertilizers
Fertilizers are materials added to the pond to make the water more
fertile (productive). As stated before, fertilization is sometimes
necessary to help a pond provide the nutrients directly needid for
fish and plankton growth. As a major food source uf fish, plankton
must be kept healthy and in good supply.
Fertilizer supplements the elements the pond gets from its own water
and soil. This is especially necessary in ponds made in soil which
has used up the nutrients once available.
A WELL-FERTILIZED POND A pond which has a lot of phytoplankton is often a bright green color.
This color indicates a "bloom" of algae. In a normal bloom, the Secchi
disc disappears at about 30cm depth; when the Secchi disc disappears
at 20-40cm, the pond is very productive and fertile. No fertilizer
is needed in a pond under these conditions. Also, if the farmer places
his arm in the pond and his arm disappears from sight at the elbow,
the pond does not need fertilizer.
There is one more a pond can become 15cm, the "bloom" sunlight from the condition when no fertilizer is needed. Sometimes
too fertile. If the Secchi disc disappears at only
is too thick. The thick layer of green blocks the
pond and no oxygen can be made by the phytoplankton.
94
//
,l\\\\x , . l\''
(-02. --
C-
p O-
WHEN TO FERTILIZE If the Secchi disc can still be seen at 43cm, for example, or if the
farmer can still see his entire arm from fingers to shoulder under the
water, there is not enough plankton. And it is necessary to add ferti lizer to the water in order to prepare the pond for the fish.
One other factor of the soil. If is small; if the should know that can also be used like the soil of which determines the need for fertilizer is the quality
the soil is very productive, the need for fertilizer
soil is not productive, the need is greater. A farmer
the fertilizer he uses on his fields, if he uses one,
in his fish pond. The fish pond soil is often very
the fields around it.
IYPES OF FERTILIZERS
The kinds of fertilizers used in fish ponds vary greatly, depending on
the amount of money which can be spent and what is available. Many
fish pond owners use organic fertilizers, or fertilizers that come
from living things; such as cow dung--because it is available on their
farms. Some big pond owners like inorganic fertilizers, or chemicals
made by man, like the superphosphates. But these chemical fertilizers
are expensive and sometimes hard to get.
Choosing fertilizer can be difficult. The following paragraphs provide
more detail about organic and inorganic fertilizers and some guidelines
to the proper use of each.
95
Vegethba mdt eA. Chopped up manioc, sweet potatoes, or banana leaves kang kong, guinea or napier grass, or other such things that have been allowed to rot for a while. The amounts of vegetable matter used as fertilizer can be as high as 5,000 kg/ha.
LU ZLd manut . Mostly animal urine containing uric acid, a source of nitrogen. It is washed out of stables into the ponds and used
in very small amounts by mixing it with other organic fertilizers
such as cow manure.
Hou4e,,x d ctap6. tncluding garbage, grass cuttings, rice husks, and
human sewage, also called "night soil".
a Ania manuA . Includes cow, chicken, duck, sheep, and horse dung. The best way to use this kind of fertilizer is tc make a "soup" of it in a tank by mixing it with water. Use the liquid part of the "soup" in the pond. Animal manure can also be placed in a burlap bag hung from a stake in the water. This way, the nutrients from the manure will be released slowly into the water without the manure itself clogging up the pond bottom. If this cannot be done, then pile the manure in the corners of the pond. Do not use too much manure; decaying manure uses up the oxygen in the pond -- particularly in hot, humid climates.
The best way to use these sources of fertilizer is to mix them all
tigether in what is know as a compost pile. A compost pile is simply
a pile of these organic materials which has been left to rot. As
the materials decay together, they produce a substance which is a
very good fertilizer. Compost piles are important: they or~vide the
very best kind of organic fertilizer for fish ponds and, in many cases,
they cost nothing.
96
ETTA1:
N' T 2^14\
97
There is now a faster way to make the compost ready to use as fertilizer.
Make the same 1.5(4 x l.5m pile of plant material, manure, and
lime. This time, however, use more household garbage and animal
manure. (Animal manure supplies nitrogen, an element used by
plants during the decay process. A good compost mixture is about
I shovelful of manure to 30 shovelsful of the other organic
materials.)
Mix the material well. Then cut all of it into small pieces, using
a shovel, machete, scythe, etc. The pieces should be about 3 to
5cm long. Cutting the material soeeds the rotting orocess. (If
animal manure is hard to get, add some inorganic fertilizer contain ing nitrogen to the ccmpost tile.)
Turn the pile every few days. Use a shovel to keep it well-mixed.
Compost piles can get too hot in the middle if they are not turned
and mixed. Put a stick into the middle of the pile. Leave the
stick in the pile for 3 minutesand then pull it out. If the szick
is hot, dry, or smelly, the pile must be turned so that the inside
of the pile is now on the outside.
Keep the pile moist, but not wet. Protect it from the rain. Animal
urine can be used to keep the pile moist and helos to add nitrogen
to the pile. A compost pile made in this way will be ready for use
in only 3 weeks.
When ready, pile the compost in the corners of the pond and restrain it
with a screen, or cover the compost with a layer of mud to hold the
plant material in place so it does not float into the pond. The compost
releases its nutrients into the pond water gradually.
APPLICAY1ION RATES
Fertilizer should be applied at a rate determined by the area of your
pond. Area is the length of the pond multiplied by the width. For
WiDTH
,EA
- LEN0ui-4 X WidTH
LENGTH
98 example, if the pond is 10m wide by 2Cn long, it has an area of square meters (mp). This is equivalent to 2/100 of a hectare.
200
The
measurements used for pond area are:
1 are
I acre
*
lOOm 2
2
40 ares = 4000m
200.,-
= x
T7,W9Z
: 20020) =
200 kg/ha
X ; X = 4 kg
lO0CUW
Most ponds are not as big as one hectare, so the farmer will determine his pond's area before using the manure.
Itwill have to
be hard for
most farmers to calculate application rates in this way, probably easy for you to develop some standard measures but it is
a farmer can
use which are based on the average-sized pond inyour area.
Often fish ponds are managed in conjunction with other animals.
Stables
are built right over the edge of the ponds, and the manure rnd urine
from a certain number of the animals ari allowed to fall
directly into the
pond. This efficient system works well for fish which can use manure as
fish food. This system gives large crops of healthy animal
fish. Fish
ponds which share the area with a number of ducks show high
yields of both
ducks and fish.
99
For the first fertilizer added to a new pond, some common rates of
application of animal manures are:
Cow dung Chicken dung 1000 kg/ha
114-228 kg/ha
100
Foods
It is important to be sure
that fish have good food. Feeding and
fertilization work together to make Jhe pond successful.
The growth of fish in ponds is directly related to the amount of food
available in the pond.
The pond must provide all the food and nutrients
fish need. But all fish do not need the same
kinds of food: different
species eat different types of food, and fish eat different foods de pending on the stage of their life cycle.
Newly-hatched fry eat from their yolk sacs until
the sacs are gone.
The fry then eat the smallest phytoplankton in the pond. As the fry
get bigger, they can eat bigger foods.
Adult fish eat the things that
their particular kind of fish enjoy--plankton, higher plants, worms,
insect larvae, etc.
101
Fish foods can be natural (those found naturally in the pond) or sup plementary (those foods added to the pond).
Natural Foods. These foods zre the phytoplankton, zooplankton, detritus
snails, worms, insects and iniect larvae, small plants like duckweeds
and various other weeds and g,.asses that can be found in a fish pond.
(See illustrations of Natural Foods at the end of this section.)
Also,
if the fish is carnivorous ard eats the flesh of other animals, small
fish are also a food source.
Some fish eat all these foods; some prefer only one kind of food.
Often a fish will choose one kind of food over another, even though
either of the foods would be eaten by the
fish if the other food were
not available. Natural
foods are the best foods for fish. The farmer
should encourage, as much as possible, the growth of these natural
foods -- through maintaining the quality of his water, proper fertiliza tion of the pond bottom and the water, etc.
Sometimes, however, the farmer must add food to the pond because the
pond is not producing enough food for good growth.
The best suople a mentary foods
farmer can put into the pond are extra natural.oods.
But there are a great number of other foods which fish will
eat.
Supplementary Foods.
Almost anything can be used as a supplementary
food, depending on the fish species in the pond.
Typical supplementary
foods are: bread crumbs, rice bran, fish meal, ground-up maize,
broken rice, boy bean cakes, peanut cakes, sweet potatoes,
guinea grass, napier grass, kang kong, manioc, water hyacinth, wheat,
silkworm pupae, and left-over animal feeds and some animal manures.
As stated previously, the kind of extra food depends on the kind of
fish. Tilapia, for example, will eat almost anything, including the
supplementary foods listad above. This is one reason why they are
such very good pond fish. The silver carp, on the other hand, will
eat only phytoplankton, even when it is a fish of marketable size.
(he farmer rust know what his fish will accept before he puts the
fish into the pond.
NOTE 70 DEVELOPMENT WORKERS zoie of these supplemental foods are better at encouraging growth than others. The value of each food is measured in terms of how quickly
and well it can help the fish gain weight. The amount of a food that
can be converted into fish flesh by the fish is called the conversion
ratio. And because these foods are given to help the fish grow, each
food has what is known in various places as a growth co-efficent, food
quotient, or its nutritive ratio.
102
The food quotient is figured by dividing the total weight of the food
by the total increase in weight gained by the fish over a period of
time.
This isdone as follows:
Food Quotient = weight of food given
Increase in we ght of fsT
For example, a fish weighing lOOg is
rate of 5% of his body weight, or 5g fed a supplementary food at a
per day.
The fish weighs 160g
at the end of a 30-day period. Therefore, the food quotient of this
particular food is:
Food Quotient = S
30 days) (160-lTOOgT-
Food Quotient = 2.5 Inother words, the fish has been able to use about 2.Sg of food to
gain l.Og of weight a day. This is a good conversion ratio.
The table shown here lists food quotients foods used with common carp.
The lower of some kinds of supplementary
the value of the quotient,
the better tile food was used by the pupae help the fish grow faster than fish. For example, dried silkworm
the conversion of foods depends upon do fresh silkworm pupae.
REMEMBER:
the ability of the individual
fish to use the food given to it. And that ability differs according
to species.
FOODQUOTIENTS OF COMMON CARP FEEDS
FOOD
Fresh silkworm pupae
Dried silkworm pupae
Chironomids
150
FU
IN
5.0 - 5.5
1.3 - 2.1
1.5 - 3.0
5.0
2.2
1.3
3.0
1.5 - 1.7
4.0 - 6.0
2.3 - 4.4
Fish meal
Rice bran
Maize
Source: B
103
104
natural foods
phytoplankton
Tuhtomona6 votzU
StaatuunchaoceAoa
Anabenopiz taitganyikae
i t y mo ni umw chel pa pt
mrW
c s-t .i
~g
n s
zooplank ton
Nauplius of Cyctop6
Cyctop6 6im~b'r-ata
MacAohix sp.
StadtAon6 sp.
Aeona sp.
105
higher plants
LMAPOLYRR"IZA
VALL15NERIA
"
CERATOI'HYLL M'
EICHORNIA
106
JUSSiAEA REPENS
VAYDRiLLA
AZOLLA PiNNATA
snails
0
A
YMNAEA SP
1' I.HYSPSI S SP
ft S
CLEOPATRA SP
PiLA SP
107
It should be clear by now that much of the success of a fish pond depends upon careful planning. Before the fanrer could build the pond, it was necessary for him to think through why he warited the pond -- for food, profit, or both, what kind of ponds he could build on his land and what
kind or kinds of fish arebest suited to his climate and pond conditions.
Only when all these factors were thought out could the pond be built.
Now, with the pond constructed, fertilized, and otherwise prepared for the fish, the farmer is ready to put the fish into (stock) the ponds
and ret to the business of raising fish.
Stocking
Stocking is the word used to describe the act of placing the fish (stock)
into the pond. The stocking density is used here to refer to the total
number of fish which can Be put into (stocked) in a pond.
Good Stoczing Den ty ood Fi.h G'tmm
Fizh G~uwich
108
The stocklq ratg is the term used to refer to the number of one species
which are put
nto a pond. Therefore, in a monoculture pond, the
stocking rate is the same as the stocking density because there is only
one kind of fish.
In a polyculture of Chinese carp, however, the stocking densityor the
total number of fingerlings, may be 20,000 per hectare.
Of this total,
the stocking rate looks like this:
grass carp are stocked at a rate
of 5,000; 5,000 are bighead carp; 10,000 are silver carp.
A Potcutte L o6 Caltp
Stocking rate and density are important. There is only enough food and
room in a pond for a certain number of fish.
The good growth of fish
depends upon putting the right number of fish into the pond.
The age of the fish must also be considered when stocking ponds.
For
example, more fingerlings can be placed in a pond than fingerlings require less food per fish than brood fish. brood fish, because
If available in the pond is not supplemented, proper stocking the food
rates and den sities are even more important.
STOCKING DENSITIES
The farmer must know how many fish he can put into his pond so that he
can get the right number--either from the market or from a local or lake. He should remember, when he decides upon this number,
stream
that
some of the fish will die--both whcn hey are put into the later. The following paragraphs provide some guidelines
to pond and
use when
stocking a pond with some of the more common pond fish.
Common Carp. Stocking densities differ with the age and size of 3 the
?Ti.I general,
the more volume of water a carp has, the better is
its growth. This assumes
that the pond contains enough food, and the
water temperature is right.
The best growth of ccmmon carp shown with stocking densities of about 10,000 to 20,000 fish has been
per
hectare; more with fry;
less with post-fingerlings. Some ponds use
109
The following paragraphs describe the proper methods for carrying new
stock from the market or river to the pond, and for placing them into
the pond."
FISH IN PONDS STOCKING There are some general rules which apply when bringing fish from one
place to another:
do not handle the fish too much
make sure the fish get enough oxygen
keep the fish from getting too warm or too cold
stock or transfer fish in the early morning when temperatures
are lower and the fish are less active.
If fish are stocked so that there is enough oxygen, no temperature
difference betwe., the stocking water and the pond water, and they are
not touched, the Fish will not be stressed and will survive the stocking.
Here are more details concerning the stocking of fish at different
stages in the life cycle.
110
When fry are being moved for a short distance a nursery pond to a rearing pond, they usually only, for example, from
are carried in small plas tic or metal
tubs, or in baskets.
, .
. ,
/"'.
Moving Fry for Longer Distances. If the fry are to be taken from a
market or river which requires a few hours travel or a long distance,
they must be protected better. One method, which can also be used
for fingerlings (and some small adult fish), is to:
Place fry into plastic bags filled 1/3 with water.
Fill the rest of the bag with oxygen. The oxygen is
put into the bag with a hose placed directly into the
water so that the oxygen bubbles into the water.
Li
~-0
112
* Change the water in the bags after 6 hours. The oxygen will
last only that long.
SMake sure the bags do not get too hot and that the tempera ture of the water in the bags stays at about the same
temperature as the water from which the fingerlings or
fry were taken.
113
ygh
114
4:
115
'ti
IMPORTAT: Check the ponds at the same time each day. Early morning
is the best time because oxygen lavels in the water are lowest then,
and the fish are more likely to have trouble at that time of day--if
they are going to have trouble at all.
116
le,
117
il'I
I
118
There are more exact ways to determine how much food to feed
the fish. Most pnnd owners feed fish at the rate of 2 to
5%of body weight per day. Therefore, 100 fingerlings
weighing 6g each (attk weight of 600g) would receive
5%of 600g, or 30g of food a day. One hundred fish of
breeder size weighing lkg each, (total weight 100.kg) would
require 5kg of feod a day.
Making such measures and calculations isnot possible
for many farmers. Therefore, it is best that they know
which foods to give, how to give thdm,and how to Judge when
the fish are or are not getting enough food.
Feed fish only 6 days each week. This will give the fish
a chance to feed on whatever food remains in the pond.
Too much food can clog the gills of fish, particularly
those fish who eat only very fine particles of food.
Do not feed fish for at least one day before harvesting
or breeding them.
When the fish eat, they void (empty)
the waste from their bodies into the water. This hap pens even more when the fish are stressed. The combina tion of food and wastes makes the water turbid and
increases the stress that is already placed on fish by
the breeding and harvesting processes.
Feed the right kinds,of foods. Some fish will eat almost
any of the foods mentioned in the section on'Preparing the
Pond.0 Other fish are not as easy to please. The farmer
will have to experiment with supplemental foods. Ifhe
gives food one day and it is not eaten, he should stop
that food and try another. Again, if he starts with
small amounts only, he is not likely to run into trouble.
While it isa good idea to test those foods most avail
able to a farmer, here are some guidelines to feeding a
number of pond fish.
Common Carp
Common carp feed well on the natural food produced inthe pond. pond owners often give common carp supplementary food, so the fish However,
will
gain weight quickly. Some good supplementary foods for common carp
are dried silkworm pupae, fish meal and clam meat.
However, these carp
will eat almost anything. Suplementary foods such as these are not
necessary. The best way to increase common carp growth rates is to
fertilize the pond %.,ll so that the pond produces a good supply of
natural food for the carp to eat.
119
Tilapia Not much is known about the feeding habits of some of the tilapia,
for example, Tilaoia nilotica. Tilapia mossambica and Tilapia zillii
are used to control fil-mentous a ,wich is a habitat for -mos-qto
larvae, thus the tilapia is used to help with malaria control.
Tilapia are hardy and accept many foods. Most tilapia ponds can be
managed in much the same way as carp ponds.
Chinese Carp
Chinese carp fry eat plankton, so it is important that they be placed
in a well-fertilized pond with a good supply of natural food. Fry
can be fed supplementary foods after a while. These foods include
egg yolk which is strained through a cloth into the pond, soybean meal,
rice bran, and peanut cake. Once the fingerlings get larger, they can
be fed like common carp.
Remember, however, that the small pond owner is likely to have Chinese
carp as part of a polyculture. If the polyculture has been planned
wisely, the Chinese carp will not need to be fed extra food.
Indian Carp
Young fry of Indian carp, like all carps, feed on the plankton in the
pond. NIormally fish ponds in India are fertilized by draining the
pond and drying, then adding a fertilizer made of some animal manure
mixed with oil cake at the rate of 200 to 325 kg/ha. This produces a
good bloom of plankton for the newly hatched fry. However, it has
now been shown that the Indian carp prefer zooplankton, though sometimes
they are given supplementary foods. After the fish reach fingerling
size, no supplementary food is given.
Note that in any pond, the fish can be kept healthy, well-fed and
growing well by making sure the pond is well-fertilized so that it
produces its own food. As a general rule, it is better for most small
farmers to work at keeping their ponds well fertilized or to find
natural foods which can be added to the pond. Most small farmers do not
have extra foods to share with fish, but they do have access to organic
fertilizer materials, such as manure.
120
CO
121
.... . .
Watch for Predators. Check the pond area for signs of snake holes,
rat burrows, eels, and strange fish which may have entered through
holes in an inlet screen for example. Any of these can be very
dangerous in a fish pond, particularly to a pond containing fry or
small fingerlngs. Make sure fences which protect ponds from farm
animals who might eat grass off the walls or break down the walls of
the pond have no breaks in them.
Not each of these things will require much time each day. But a good
pond manager will at least check each of these items daily.
MONTHLY MANAGEMENT Ponds which are managed well day by day will require little other
treatment. However, the following things will probably require more
careful attention every month or so:
Check the pond walls. Cut grass which is too long or
plant more, ifnecessary.
Check the pond bottom. If there is too much buildup of
silt and organic matter, shovel or scoop this material
out.
122
5ILD UP OF DECAYIN~r
ATTEPR
POND BOTTOM
123
124
-0
A 14S
COUNTING FRY Fry are very delicate and must be handled gently. counting them:
vo
asin
125
126
For a farmer who has only one new pond, it is probably a better idea
for him to start with young fingerlings. This will give more chance
of success than starting with fry.
This isnot to say that a farmer who has only one pond cannot start
his fish crop from eggs or fry. He can. One way this can be done is
to keep the eggs ina washtub or large container rather than a pond.
The eggs must have plenty of oxygen, so the water must be changed often.
Any unfertilized eggs must be removed so
that they do not cause in fections in the fertilized eggs. Unfertilized eggs are white; ferti lized eggs are yellowish red.
Keeping fry ina smaller container isa good idea because it allows
the farmer to better control the surroundings. Fry often get
bacterial and fungal infections and are a favorite target of birds.
Again, the water must be kept rich in oxygen and food which can be
eaten by fry.
The care of eggs and fry isvery difficult and very important. A
farmer who wishes to breed fish must certainly work to gain experience
handling delicate eggs and fry. A farmer who wants only a food source
inhis backyard may wish to take the easier road and start with
fingerlings.
The size of fingerlings depends upon climate, water temperature, food
given, and the number of fish stocked in the pond. The following are
some average sizes and weights common in the Philippines:
Average Lengths Milkfish Tilapia Silver Carp Common Carp 6.57cm 6.33cm 5.64cm 7.39cm 7.39cm Average Weights 2.9 5.8 5.6 7.1 7.1 grams grams grams grams grams
Fingerlings may be fed supplementary food if it isnecessary. Remem ber that fish usually receive supplementary food which is about of their body weight per day. This was discussed in more datail 5%
in
the section on preparing the pond, so there is no need to go into
detail here.
It probably isa good idea, however, to note again that farmers should
proceed slowly when giving supplementary foods. Add only small amounts
of food and watch the fish carefully to see how they accept it. And
the most importunt thing is to make sure the pond is producing enough
of its own food.
127
If the guidelines for management, discussed earlier in this section, are followed, the fingerlings should grow well. When the fish reach sOe people a good size (the size preferred in the farmer's area *-like smaller, rather than larger fish), they can be harvested and
sold.
,,
Il/IAI
(0".
128
Other characteristics used in choosing good brood stock are relative size
and the large, rounded abdomen in the female fish.
Choosing brood stock of common carp is more difficult. of these fish are:
. moderately soft body
The characteristics
129
The brood stock must be well cared for. If they in good health, the
eggs will be healthier. It is probably more important to feed brood
stock with supplementary foods than it is to give supplemental food
130
to fish at any other stage of growth. Feed them rice bran, soy bean
cakes, or other processed foods at a rate of 5% of day. They should be managed carefully according to body weight per
the general guide lines discussed earlier. Remember:
brood stock should not be fed for
at
least one day before they are caught for breeding.
When caught by net, examine the brood stock carefully and handle them as
little as possible. Use a cradle to handle and carry the fish from one
pond to another.
They should be carried to a spawning pond, stocked in
the proper manner, and left to spawn.
After spawning has occurred, the
brood fish should be caught again and carefully carried back and released
into their brood pond.
Always remember to treat brood stock well, and never select spawning which does not show the proper signs of readiness a fish for
to spawn.
(See the following information on spawning behavior.)
M'
The farmer who sees his common carp doing this has a good indicator that
his fish are ready to spawn.
When comon carp are ready to spawn, the female carp begins to swim in
and out of the plants. She then releases her eggs on the plant roots.
The male follows her very closely. As she releases her eggs, he releases
his sperm (milt); the sperm fertilizes the eggs. Carp eggs are slightly
sticky adhesive) and they stick onto the plant roots just under the
water surface until they hatch. Depending on the temperature of the
water, the eggs hatch in 2 to 6 days.
The new commn carp fry feed off of their yolk sacs for another 2 to 6
days, until it is absorbed, and then begin to feed on the zooplankton
in the pond water. The carp can spawn all year round in nature, as long
as the water temperatures stay high, because a carp is capable of
breedinq once every two or three months.
)-2)
cormmon caltp
I1 2
A I:akaban is a floating mat that uses a fiber like inkjuk, or beaten palm
bark or leaves that have been shredded into long fibers. These fibers
are bunched together and tied in the middle.
The bundles are then nailed
down between two long pieces of wood or bamboo and floated Just under the
water surface, with the ends hanging down into the water.
This will
look like the roots of water plants to the fish.
A KAKABAN
A kakaban is better to use for carp breeding than plants because it can be
boiled and sterilized each time it is used.
This will prevent any fungus
or bacteria from attaching the newly-laid eggs.
133
The female will deposit her eggs, about 75 to 200 of them, ;nthe nest,
and then the male releases his milt. The female picks up the eggs and
the milt in her mouth, so the fertilization of the eggs actually takes
place in the females' mouth.
Tilapia often are called "mouth breeders."
The eggs remain In the females mouth until they hatch -- 3 to 5 days.
Then the fry stay in the female's mouth until the yolk sac is gone.
During this time, the female does not eat.
As the fry grow, they continue to hide in the mother's mouth when they
are threatened. The main reason for this mouth-breeding is for protec tion of the young fish, since the tilapia have relatively few eggs
compared to some other pond fish.
filapia is also a favorite food for
a number of predators. Because the fry are so well taken care of by the
mother (and even sometimes by the father fish), these young fish are
easier to raise than some other species of fry.
W~pA ~
134
Tilapia will
also spawn in ponds that do not these ponds, place large-mouth pottery jars have loose bottoms. In
sides on the pond bottom; the tilapia will
or wooden boxes on
their
use these containers as nests.
Young tilapia mature at about 3 months, when they are only 6 to 10cm
long.
They can then breed every 3 to 5 weeks, as long as the water is
warm.
In areas near the equator where the water
isalways warm, tilapia
can breed almost continuously.
When a fish begins to breed, his energy goes
into the development of his
reproductive organs, not into bodily growth.
The main problem with
breeding tilapia in fish ponds, therefore, this fish. Reproductirvo can be controlled is the rapid reproduction of
by sorting the tilapia by sex
and placing them into separate ponds, or by producing a monosex culture
by hybrid crossing. However, these methods can usually be done only by
large commerical
or government hatcheries where conditions are controlled.
The problem of fast breeding
in tilapia ponds can also be controlled by
using some natural predators of tilapia in the often used are catfishes of the genus CaAiZ" pond.
The predators most
Angutta japonca, and some other carnivorous and, sometimes, eels like
fishes like SeArnodiwL
U9oA in0(A, a polyculture with tilapia that are reproducing. These
predators will eat the young fry, allowing the adult fish to continue
their growth by having no competition for the available food.
135
tovt
,-, ./,.
CL P
Chinese carp brood stock must be well cared for, like all brood stock.
They must be allowed to live undisturbed until time for spawning. How ever, the Chinese carp must be induced to spawn (see Induced Spawning).
b p
ighead
136
~Indian
. tp
INDIAN CARP --
Spawning in Ponds
Good Indian carp breeders are sexually mature when milt comes from the
male as it is pressed on the stomach. Ripe females have soft, rounded
bulging abdomens and reddish genital openings. The breeders should
be kept separated by sex in ponds prior to the breeding season, so that
they will readily spawn when introduced Into the breeding hapas.
Usually one female is placed into a hapa with two males to
insure that
fertilization occurs.
If a farmer can place the breeding hapa into
a source of lowing water, he may be able to breed these fish naturally.
If not, Indian carp must be bred with Induced spawning methods.
137
The hapa is held in place Inside the pond with stakes of bamtio or other
wood. The breeders are put Inside the hapa. Kakabans are placed below
the water surface, and the top of the hapa is closed so that the
breeders do not escape while m&ting. After spawning, the kakabans can
be removed and taken to the nursery pond and the breeders released into
the pond. Hapas can be used to spawn other fish as well.
THE GOURAMI
-4
Spawn nq in Nature and Ponds
The gourami build ne ts out of plant materials to lay their eggs. The
The fry float belly-up for 5 days until
eggs hatch in about 30 hours. feeding begins. The gourami can spawn all year round in warm water
conditions.
This is a very good pond fish, and very easy to breed have a well-fed brood stock. The natural food of the leaves of plants like Colocasia and Carica. They can bran before breeding. Usually 10 females and 5 males ponds as small as 100m? and the eggs float until they
as long as you
gourami is soft
also be fed rice
are stocked in
hatch.
138
SnakeA~Uj ouunm q
To breed the snakeskin and three spot gourami, place the ripe fish into
a well-oxygenated pond that has
a good growth of aquatic vegetation,
particularly Hdrilla verticillata. These fish will continue to spawn
0
as long as the water temperature stays at 26 - 28 C. Hatching takes
place about 2 days after spawning, and the fry absorb the yolk sac
within 3 to 7 days.
The kissing gourami spawn at 6-month intervals and spawn within 18 hours
of stocking in the pond.
Some of the eggs may be eaten by the parent
fish, so there must always be abundant vegetation in the spawning pond
to prevent this.
The eggs hatch in 2 days and float on the surface for
3 to 4 days. The new fry eat the decaying plants and plankton in the
pond.
CLARIAS CATFISH -- Spawning in Nature and Ponds
Clarias macrocephalus spawns during the rainy season in nests on the
t-t"of natural waterways, while Clarias batrachus spawns in horizon 0 tal holes in the banks. Hatching takes place after 20 hours at 25
32 C. The fry are then collected by hand net from the nests. There are
2,000 to 15,000 fry in each nest.
Clarias catfish will spawn naturally in ponds, but induced spawning
mettods may be used if necessary.
at h (
139
HETEROTIS NILOTICUS
--
The eggs of HeteotL are about 3mm in diameter, and are laid in the
bottom of the nest and then fertilized. One of the parent fish is
always in the nest to circulate water over the eggs (to give them
oxygen). The eggs hatch in 4 - 5 days. The fry travel in a "school"
and stay with their parent fish for several months after hatching.
The fry are very delicate, and should not be handled for a while.
140
MILKFISH
--
Milkfish spawn in saltwater during the rainy season. The fry are caught
along the shore line at breeding season (which corresponds to the
rainy season) and then transferred and acclimatized to freshwater ponds.
This is done for the most part in the Philippines and in some other
Southeast Asian countries like Indonesia and Taiwan.
Milkfish cannot be bred in ponds.
141
Induced Spaning. Induced spawning means making the fish produce eggs
an mt when they will not do so naturally. Induced spawning is done
when the pond conditions cannot be made to encourage natural spawning,
or when the fish are not ready to spawn when the farmer wants them to
spawn.
Spawning can be done by three methods:
* hormone injection * hormone iniection with stripping * stripping Each of these methods has advantages and disadvantages.
Hoimone Injection. Hormone injection is the most common method of induced spawning, and it requires certain kinds of equipment: hypodermic needle and syringe
mortar and pestle
saline solution or distilled water
centrifuge test tubes
E dissecting kit
SALINE
SOLUTION
HYPODERNikC
D
PEST LE
O ~TEST
DSECTI ON K*iT
142
This technique uses the pituitary gland (the hypophysis) of the fish.
This gland contains the substanceg( hormones) that trigger the reproduc tive organs of the fish to start developing. When these hormones are
taken from a ripe fish and injected into a fish that is ripe, but has
been unable to spawn, the injected fish will spawn in 6 - 12 hours.
The ripe fish must be killed to get the pituitary gland out. This must
be done very carefully. The gland is very small: less than lImm in
diameter in the common carp, which has a relatively large pituitary.
The pituitary gland is a round, yellowish-red organ located in the brain
pan of the fish. Here is the method commonly used to take the gland
from the fish:
Use a mallet or dull knife.
Hold the fish near the head with one hand.
Hit the fish above the eyes at the point where the skull begins.
This will kill the fisi,.
Make sure to hit straight and up a little. A solid hit should
dislodge the skull.
Slit the skin around the skull just enough so that the skull
can be lifted straight up easily. Do this very carefully.
Lift up the skull and expose the brain pan. The pituitary
gland should be right on the top as the skull is lifted.
If located in this way, the pituitary gland is relatively easy to
find. However, this must be done carefully. If the skin is cut too
much, or the fish is handled too much, the contents of the brain will
move and the pituitary will be hard to locate. The brain contains a
number of fat deposits which are yellowish and could easily be confused
with a pituitary by someone who was not familiar with that gland.
Most farmers will not be interested in doing hormone injection spawning.
But you should be familiar with and be able to do it. Steps for
processing the pituitary gland and giving the injection are given below:
Select the fish you want to spawn and weigh Select them. fish. taries them.
the fish that will be killed for their glands and weigh
Always match the weights of the donor and recipient
If a donor is 1.5kg and the recipient is 3kg, use pitui from two 1.5kg donors.
143
144
MAKIWG A CEh7'RIFUGE
Tools and Materials:
1 hand drill
1 ?Ocm piee small wood (or bamboo) dowel rod
* 2 metal cigir tubes (or plastic, or rubber hose with clamps) * 2 pieces meolum wire (long enough to wind around the tubes 6
or 7 times)
* 1 piece heavy wire about 9cm long (old coat hanger will work)
* cotton balls ar pieces of soft material
* 2 test tubes or small clean glass bottles * string, tapes, and nylon fishing line
HEAVY WiRE
METAL TUBES
WOOD
OTTON BALL E~ST TUBE
CILD2Ocm WIRE"DWE
HAND
DRILL
]_
Construction Steps:
* Drill hole through one end of dowel rod about 1cm from the
end.
Remove drill bit from drill.
Insert dowel rod into drill bit hole, leaving end with newly
drilled hole at opposite end on top.
145
146
147
the fry are hatched, they can easily be transferred without touching
them at all. This is good, because Chinese carp fry are very sensitive
to handling stress.
After the carp spawn, the eggs are collected by net or by "raining
the breedling pond, and they are placed in the hatching bags (or
shallow trays) as soon as they have hardened after ferllzation (1 to
2 hours). The eggs hatch in 1 - 2 days depending on the temperature,
and then absorb their holk sacs in another 3 - 6 days.
As soon as the fry absorb their yolk sacs, they should be transferred
in the hatching bags to nursery ponds. The nursery ponds should be o.5
to l.Om in depth and the oxygen level should be at least 4ppm for good
fry growth.
The spawning of Chinese carp is a very complicated business and is usually
done inside carp hatcheries so that all conditions can be controlled.
In China, the carp hatcheries sell their fry to fish pond owners who
then raise them to marketable size.- For most farmers, common carp is
a much easier fish to work with and is just as valuable for food as
are Chinese carp.
INDUCED SPAWNING OF CLARIAS CATFISH
fishes are injected with pituitary extract at
mactoceplw-b_ The CMAi a rate of 13 to 26mg/kg at 25 - 32C. Spawning occurs within 16 hours.
Larvae (fry) dbsorb the yolk sac in 5 days, and are trdnsferred and reared
in ponds only 18cm deep. The best food for fry is zooplankton, but
after 2 to 3 weeks, trash fish may be added. They can be fed rice bran as well, and later on a mixture of trash fish, rice bran, and broken rice. In Thailand this sort of production gives yields of 97,000 kg/ha per year. Ctatixu catfish are used in fish ponds throughout Southeast Asia now, and are enjoyed for their good taste.
148
Harvesting Fish
Harvesting is the collection of fish from a pond or for cooking and preservation for family use. to collecting all the fish or tq taking out only (this happens often in tilapia ponds having both
If the pond can be drained, harvest the fish by draining the pond into
the catch basin and collecting the fish with a scoop net. If the pond
cannot be drained, drain out as much water as possible and use a series
of nets to catch the fish.
Types of Nets
There are different kinds of nets which can be used in ponds. Some nets,
such as the one shown here are gill nets. Gill nets often have mesh
sizes from 2-3cm; they are often used to harvest the largest fish in a
pond and leave the smaller fish until they grow larger.
WEIGHTS
They are called gill nets because the
fish pokes his head through the net
mesh, and is caught around the gills as
he tries to wiggle through the net.
150
FL OATS
WEIGHT3-"
Netting a Pond
Let out as much water as possible.
NEVER LET THE WATER OUT COMPLETELY.
As
the fish have less and less water in which to live, they become
excited and use up more oxygen when there is less available. Plan on
harvesting while the water is draining out so the fish are caught before
they are stressed.
Or, drain the pond almost completely, and then let
water slowly trickle through while netting the fish.
151
USING A SEINE Place the net at one end of the pond and slowly draw the edges down the sides of the pond. Bring the middle of the net
across the pond.
When near the other side, begin pulling the edges up onto the bank so that the net forms a u-shape in the pond. Pull up the bottom rope of the net along the pond bottom until it breaks the water surface. At this point the net is a bag shape and will hold the fish in (some seines already have a bag woven into theml.
"
,,."
-. /
" -7 ;
'.
-
" . .
'.'..'-
7.!
om'., '
152
Pick the fish up one by one and transfer them to buckets or tubs of
clear water for later weighing and transport.
OTHER HARVESTING METHODS Fish also can be harvested by other methods. One method is to catch them with a hook and a line, but this
method is time-consuming. In some parts of the world fish are harvested
by dynamiting or poisoning the water. But these methods are dangerous
and should never be done in a pond or any other waterway: dynamite
and poisons can kill people and other animals, in addition to fish.
NEVER HARVEST FISH BY DYNAMITING OR POISONING THE POND. There are
easier and cheaper methods than these.
153
-to
Transporting fresh fish to market must be carefully done, so that the fish are not damaged. Usually, fish are handled in the same way they were handled when put into the pond. If it is not possible to get the fish to market right away, they must be preserved -- either on ice for quick sale in a nearby market; or salted, dried, smoked, or canned if noing to a distant market. These methods are discussed in the next section. Remember: Fish spoil very quickly in warm temperatures. the fish right after harvesting. Sell or preserve
After Harvest
After the pond is harvested, it should be prepared for the next stocking
of fish: Plow the bottom of the pond
Clear out predators, sticks, rocks, etc.
Dry the pond bottom until the soil cracks
Put lime on the pond bottom
Wait two weeks
Add water to the pond
Check the water quality
154
*Market
Begin again
"./~ ...
~ ~tl
I..
..
'
155
MAKING A SEINE
A seine can be made using materials found in the market. needed are:
rope
* cork floats
* lead sinkers (or something heavy to help the net sink)
netting
. sewing needle for nets
The directions for making the net are as follows:
Tie a rope that will be used for the top and bottom lines
between two trees. Use nylon ropeif possible, because it
will last longer than cotton or hemp.
* Mark each rope at 15cm intervals. Make sure the rope is
longer than the final net by a few meters.
Stretch the netting until the meshes close completely; then
count the number of meshes in a 23cm section. Good netting
for a general seine will have 6 to 9 meshes in a 23cm stretched
section.
The materials
BOTTOM ROPE
IHT5
TO RPE
,>
/..
T---. -FLOAT,
NYLO S RI NG N T + NEEDLE
----
NETTiNG
156 Use nylon s ing that is very strong. Wind a long section on
a net needle. Then tie the end onto the lead line rope (top
rope) at the first marking. Pass the needle through the num ber of meshes counted in the 23cm section of netting. Tie the
string on the rope at the second marking.
Repeat the process until the last marking on the top reached.
rope is
Pound the sinkers, or string them, onto the bottom rope at the
15cm intervals. Tie the cork floats onto the top rope at the
same intervals.
String the bottom line onto the netting in the same way as the
top line.
REMEMBER:
157
Preserving Fish
Fish that are not taken to the market fresh must be preserved in some way
after harvesting. All fish have bacteria in their intestines; as soon as
they die, these bacteria begin to multiply and the process of decay begins.
So the first thing which must be done -- as soon as possible -- is to re move the intestines. After this is done, go on to preserve the fish in
the way chosen.
There are a number of ways to preserve fish: discussed here in some detail.
salting and smoking are
Salting Fish
Salting is a very old method of preserving fish. Salting derfeds on the
size of the fish, the species, and on the amount and quality if the
salt used. Fish which have been salted well last a long time without
spoiling.
The most important factor in salting fish is the quality of the fish
being salted. Use only fresh fish: fish which have been lying around
for hours are not good for'salting. Also, use only clean equipment end
clean fish.
PLEASE READ THE DIRECTIONS THROUGH CAREFULLY BEFORE BEGINNING.
TOOLS AND MATERIALS
158
ANLVN
There are four major steps: gutting and cleaning; salting; wa:hing and
drying to remove excess salt; and, finally, air drying.
Gut and Clean the Fish.
159 Gut the fish by cutting along the belly from the gills to
the anal vent.
Remove the guts and the black membrane in the gut cavity.
Cut off the head now, if preferred; it is not necessary.
* Bleed the " n by removing the gills and all blood vessels
after cutting open the throat.
small fish
Cut the fish into the right shape for salting: may be left whole; larger fish should be split in half from
head to tail, so that all the fish flesh will be exposed to
the salt.
( ii((/~~5PI
NAL COLUMN
Continue to
place fish, then salt, almost to the top the container.
Place the last fish layer with the skin side up.
Sprinkle
with salt; the last layer must be salt.
Place boards and weights on top of the fish in the con tainer to press them down.
Leave the fish in the container for 15 days. Add salt
as necessary, until
the fich are "struck through" - thoroughly full of salt. As
the fish lie in the salt, the
salt draws out all the moisture in their flesh.
This
as moisture forms a solution (brine) with the sait
the
to salt dissolves. It is necessary
add more salt
160
~CLEAN
FiSH
161
162
FISH Soak salted fish in fresh water overnight. Change the water at during this time. The soaking removes the salt; the longer the least once
fish is
soaked, the more salt is removed. After the fish has been soaked, it can
be used in any way that fresh fish is used.
Smoking
Fish
163
Spoiled
Fish
rn
LEFTI
Diseases
FUNGAI
DISEASES
Gill Rot. This is a disease caused by the filamentous fungus, 84anchi, anguinis, This disease is first noticed by a red spotting-on t-e
myc" gill%. Latc,, ne gills become greyish-white and stop working. When
the gills stop working, the fish suffocate and die. Gill rot is iost
common during the hot part of the year and is sometimes associated with
large amounts of dung and a "bloom" of plankton.
166
Treatment:
Remove dead fish from the pond; the remaining fish
will probably recover. Drain the pond and dry the
bottom. Treat the pond with quicklime or copper
sulphate to kill the fungus spores.
Fill the pond
again. Add quicklime every few weeks until there
is no more sign of the disease.
q"
I.
MiCROScoPiC
NGAL SPORES
Saproleqnia.
This fungus is often associated with Gill Rot. It attacks
weakened places (e.g., bruises from handling) on fish. Since it hits
already weakened fish, Sapiofegnia attacks fish already trying to fight
other diseases. .a=ofecgiUa looks like fuzzy, white cotton wool and is
often in tufts on the body of the fish. Sapo teeqnin by itself can kill
eggs and fry, but does not kill adult fish. Indian carp are very sus ceptible to this disease, and common carp eggs are attacked frequently.
Treatment: Use the same treatment as outlined for Gill
Rot.
Furunculosis.
This is the most important sease causes ulcers or abcesses in muscle the skin, and, eventually, becomes a site SapioCegn~a.
This disease attacks in the in more temperate species, like trout.
Treatment:
Drain the pond and treat it with slaked lime.
Disinfect every tool used in the pond (nets,
feeding rings, etc.).
167
Infectious Dropsy. This is caused by the bacteriunRPeudomona4 pwictata. The symptoms are a swelling of the fishes' belly with water, ulcers on
the skin, lengthening of the fins, and deformation of the backbone.
Treatment: Prevent diseased fish from entering the pond.
Bury and burn the dead fish.
Columnaris. This is another bacterial disease which causes discolored
patches on the body, loss of scales, and, often, death. This disease
can look like a fungal disease, but it is not. If possible, it should
be examined under the microscope for positive identification. It is
caused by the bacteria Chond'tococ cotuinnwrJ and Cytophaga cot&nais and isoften associated with low oxygen leveis.
Treatment: Give fish a feed which has terramycin in it. If
it is very bad, place each infected fish in a dio (bath) of copper sulfate (2minutes in a solution
of 1 to 2,000) or a dip of malachite green (10 to
30 seconds in a solution of 1 to 15,000). Treat
the pond with 1 ppm of copper sulfate.
PROTOZOAN
DISEASES
THE CYCLE O
TCH vrSASE
PON
BOTTOM0
Ichthyophthlrius multifilis. This is the worst protozoan disease. The "ich" disease iscaused by a ciliate which forms white spots or pimples on the skin and fins of the fish. Each parasite produces thousands of spores, which can then infect other fish in the pond.
168
Treatment: Drain the pond, and lime it. Or treat the fish
with chemicals as follows:
Formalin Malachite green Methylene blue Acriflavin Salt 200-250ppm I5ppm 1.25ppm 0.5ppm 2ppm lOppm 7,000ppm daily bath in pond daily bath/30 minutes inpond daily bath 3-20 daily baths several daily baths
Costia and Trichodina. These are two other ciliate diseases. They are
causec by miicro3coplc organisms which attack the skin of fish and cause
lesions. Tilapia, the very rosistant fish, are attacked by the T iN
protozoan.
. I, / "
~COST
IA
TRICHODINA
These ciliates cannot be seen by the naked eye, but the lesions and sores
that they cause can be seen by looking closely at the fish.
Treatment: Add 3ppm of potassium permanganate to pond. Or dip
the fish in baths of 5 to 10% sodium chloride (salt)
for 5 to 20 inutes daily for up to one week.
m
CRUSTACEAN PARASITES
Lernea. The anchor worm is the most common disease of this type (acopepod).
TFT-swrm attacks the gills or any other part of the body. Itburrows into
the fish, leaving its two eggs cases protruding on the outside of the fish.
Lemea causes red sores, and makes the fish thin so that their market vaiue ismuch lower.
169
ILERNEA
Treatment:
Add castor oil in a thin film over the surface of
the pond. Treat fish infected with young Lvinea
in a formalin bath, or remove eich parasite--y--and.
AP, ULU,,S.
WORM PARASITES -Most of these are external parasites. Dactylogyrus. Thi.: parasite attacks the gills of young fish.
The fish
are exposed this worm when they are between 2 and Scm long.
to Treatment: Manage the pond well so that fingerlings
grow rapidly past the stage when they are
susceptible to 9jL-y,.
Gyrodactylus. This parasite burrows into the blood vessels of fish
through the skin, causing the fish to appear reddish with sores. This
worm can cause fish to die from emaciation.
170
General Treatments
Farmers often will have trouble finding the proper chemicals for treating
their ponds or deciding which disease the fish have and which treatment
to give. Here are some general treatments: any of these treatments will
help an infected pond.
Baths: Potassium permanganate Salt Copper Sulfate Forma'iin Malachite green 4ppm
3-5%
S00ppm for 1-2 minutes
250ppm for 1 hour
67ppm for 10-30 seconds
Other
Problems
171
Predators
Other problems occur in fish ponds when other animals eat the fish.
Frogs, snakes, and birds eat young fish and must be kept out of ponds.
The worst predators, of course, are carnivorous fishes, like the
Cftvins catfishes. Prevent these fish from entering the ponds by sLreenlng the water inlet.
In any pond, all unwarted (trash) fish and predators must be removed
If the pond can be emptied, simply drain the
beftre stocking the pond. pond, plow and dry the bottom, etc. If the pond cannot be drained, seine
the pond as completely as possible. However, many fish escape the net by
staying at the edges of the pond. The best way to get rid of the
predators is to poison the pond water in a pond which cannot be drained.
USING POISON The most common poison for use in fish ponds is rotenone.
Rotenone can be purchased -- as a liquid or powder -- or it can be gotten
from the roots of the dirris plant. To make rotenone, collect derris
roots and pound them until a milky-white fluid can be squeezed out. This
fluid contains rotenone. Apply one kilogram of derris root for every
hectare of pond surface area. If using powdered rotenone, use only 0.05
kg/ha. The powder should be dissolved in water and dipped into the pond
from buckets.
Other poisons used in fish ponds are quicklime, teaseed cake, camelia
seed cake, tobacco waste, and powdered croton seed. These are some
172
application rates:
Quicklime: 160kg/ha
Teaseed Cake: 150kg/ha
Camelia Seed rake 50 to 200kg/ha, depending on depth
Powdered Croton Seed
Seed: 50 to 200kg/ha, depending on depth
Tobacco Waste: 150 to 200kg/ha
Most of these natural poisons will degrade (break down) and disappear
from the water in 7 to 12 days. After this period, seine the pond again.
Ifno live fish are caught, stock the pond.
There are many chemicals which can be used to poison predators in fish
ponds. However, many of them stay in the ground too long.
Others a.e
dangerous. One of these chemicals which can be used safely issaponin,
which isa component of Teaseed Cake. Apply a dose of O.5ppm in the
pond.
Inmost places, there are fishermen and farmers who know of some local
plant which causes fish to die. These are all better sources of poison
than chemicals.
Many times, when there isa tree that overhangs a fish will be killed when the tree leaves drop into the pond. Watch pond,
for
plants which do this, and use them in ponds instead of poisons in a
chemical form.
DO NOT USE CHEMICALS LIKE ENDRIN, DIELDRIN, AND DOT INPONDS: THEY CAN
LAST INTHE GROUND FOR YEARS, AND LATER, KILL THE POND FISH. NEVER USE
POISONS WITHOUT FIRST CHECKING WHETHER THEY CAN BE USED IN PONDS.
SOME
POISONS KILL OTHER ANIMALS AND HUMAN BEINGS, AS WELL AS FISH.
SUMMARY:
DISEASE
Gill Rot
Saprolegnia Furunculosis
infectious Dropsy Columaris
Quicklime
Copper Sulfate
Quicklime Copper Sulfate
Slaked lime In
Drained Pond
Ich
Ichthyophvthjtiw
muZiAZZ
'79
-'
'~~'
.--. A
Ijv
P
1
S
)L
~
I.>
r~
j
;~i
r~
r~
IA ii
Culturing fish i/
waters held by dams
and reservoirs can
be done more easily
if the fish are placed
in fish cages and
pens. These structures
176
In Cages
In many parts of the world, the only water available is flowing water
or large bodies of water where it is not
possible to divert the water
Into a pond.
In these waters, it is possible to grow fish In small
cages.
Cage culture can also be practiced in areas like swamps where
there is water not being used for any other purpose.
Cages can be rectangular boxes, bamboo cylinders, or anything that
can be floated in a water current so that
the water passes through.
d'wpped into the wate i fom the 6a~meA's hou6e and aniat 4hefteA..,I
'
177
Fast flowing water is best for cage culture. If the water is not flowing
very fast, problems such as oxygen lack and competition for food can
occur. These can be big problems in cages because there are usually more
fish placed in the small area of the cage than would normally be in the
same area in the pond.
Cage culture is still experimental, but in ideal conditions, good growth
rates have been shown by fish that were grown in cages and given extra food.
s.A
A-.
- r.
-0
Cages also are used inside ponds for holding fish between harvest
and the time they are sold.
And, sometimes, cages are used
as breeding tanks -- like hapas.
Cages are also used to carry
fish caught in rivers to market,
strapped alongside a boat.
In Pens
Fish can also be cultured in pens inside lakes or offshore areas. Fish
culture in pens has been done in Israel
and Scotland for years, and.is
now being done in some Asian countries. Pens are constructed of bam boo or wooden poles that are forced down into the lake or shore bottom.
Then nets are strung from pole to pole to form an enclosure. The nets
are anchored into the lake bottom with weights or sinkers, and the fish
are placed inside the pen for culture. Fish grown in pens can be
larger
controlled a little better than fish in cages because pens are
(fish pen: 3n be comparable in size to regular fish ponds) and provide
more area dnd more food.
178
Fish pens placed in fertile (productive) lakes have very good growth
rates.
In a fish pen placed in a major lake in the Philippines, silver
carp stocked at 7 grams gained an average of 4 grams a day in a 52-day
growing season.
Fish pens have many good points:
they require no extra feeding of fish,
no fertilization, and vury little i'mintenance (although a lot of care
is given to the nets).
The fish are stocked and harvested later at the
end of their growing season.
Fish areas where the
water is not very productive, but pens can work in
in these areas, the fish must be fed
supplementary foods.
Feeding rings are used so the food will
stay in
the pen and not float out into the water.
Fish in pens are usually
harvested by gill nets; seines also may be used.
STAKES
FLOATS
SIVEVIEt; OF AN4
OFFSHORE
FISH PEA'
STAKES OR WEIGHT
"
179
In Rice Paddies
This manual has already mentioned the practice of culturing fish in fields with rice. Here isfurther, brief mention of that subject.
//;
k(((,
The farmer digs deep trenches all along the dikes of the paddy.
He then
floods the field and plants the rice.
After the rice has grown to
a height of 5cm or so, fish can be placed into the paddy field.
This culture method can be used only with fish that are resistant to
low oxygen levels and are not harbivores - herbivores might eat the young
rice plants. Clarias catfishes are good fish to culture inrice
paddies because~ave accessory breathing organs which help them to
180
breathe even when the paddy gets dry and the water in the trenches gets
very low.
After the rice is harvested, the fish are caught in hand nets and sold.
This is not really a culture of fish, but a culture of rice with some
fish added.
It can be an easy way for a farmer which to build fish ponds to increase the total who has no extra land on
production of his land.
181
Glossary
atea the length times the width of a piece of land or other surface.
back P4mkng - forcing water in the opposite direction from its normal flow. boaibeL6 - sensitive organs that hang down on the sides of the mouth of certain fishes.
b e having base forming elements (alkaline on reaction).
btoom - a very good growth of algae in a pond that has a strong green
color.
bottom Jeede'4 - fish that feed on bottom organisms (organisms that
live In mud on the pond bottom). bLeeding - the cycle of reproduction in animals. bxine - water that is saturated with common salt, or the water from a salt water body (the ocean). bAood ponda - ponds where the fish used forbreeding are kent. bood atock - tne fish used for breeding in fish ponds. cage - an enclosure to hold fish in the water. captv.ity - the state of being held in a confined place (fish in ponds are captive). cAnvoite - an organism that eats animal products.
182
6inge4&ng dL4hcuttvue
genit t opeitin - the opening on the fishes' body where the eggs or sperm are released.
giM the part o: a fish that allows it to breathe in the water.
g~avty the tendency of things to fall downwards towards the center
of the earth.
/utpa - the mesh enclosure in ponds where fish can be spawned.
heAbiuore - an organism that eats only plants and plant products.
183
natwma
omn.Lvote - an organism (like man) that can eat both plants and animals.
opeAcu.um - the gill covering.
oxygei - a gas that is necessary for all life.
pm-u - enclosures for fish culture on large bodies of water.
phqytopuik. on - tiny green or brown plants that are irrcscopic,
free-floating inwater, that are used as food by fish.
phowtoAyn.heALs - the process on which yreen plants produce food for
themselves and release oxygen into the water.
pJ. y g ,ito
gland that releases hormones controlling the
- the reproductive cycle in animals (like fish).
p~nktoan - the tiny plants and animals that grow in ponds that are
eaten by fish.
ponds - any enclosure that holds water so that fish can be grown
inside it.
predatoi4 - animals that prey on other animals.
c ptod cwt vity - ability to grow food Ina pond, whether it is plankton
or fish.
184
st6 any change that is not normal in the environment that creates
problems.
tA.h 6iZh - fish not wanted in the pond, or fish that are too small to
eat or spoiled fish.
tOzatv1gkt - impermeable.
zoopfank.tn - small animals in ponds that can be seen with the naked eye.
185
Resources
Standard methods 1. American Public Health Association. 1971. for examination of water and wastewater. 13th ed. Am. Pub. Health Assoc., Washington, D.C. 874 p. 2. Anderson, Steven E. 1973. A manual of fish fanning for tropical Africa. University of Minnesota, St. Paul, Minn.
46 o.
(xeroxed copy)
A 3. vault, James W., Jr., Iq65. Preliminary studies with qrass carp
for aquatic weed control. The Progressive Fish Culturist.
27 (4): 207-209.
4. Avault, James W.,
Jr., and E.W. Shell. 1966. Preliminary
186
14. Crane, John S., et al. 1966. Togo fish project manual. United
States Peace Corps. Oklahoma University, Norman, Olkahoma.
158 p.
15. Delmendo, Medina N. and Robert H. Gedney.
1974. Fish
farming in pens a new fishery business in Laguna de Bay.
Laguna Lake Development Authorit,-, Technical Paper 2.
Pasig, Rizal, Philippines.
16. Denyoh, F.M.K.
1966. Pond fish culture development FAD World Symposium on Warm Water Pond Fish Culture. in Ghana.
Rome, Italy.
17. Dillon, Olan W., Jr.,
et al. Warm water fish ponds. Farmer's
Bulletin 2250. USDA. Washington, D.C. 14 p.
18.
Dyche, L.L. 1914. Bulletin on ponds, pond fish, and pond fish
culture. Part Ill.
State Dept. of Fish and Game, Kansas.
Kansas State Printing office, Topeka, Kansas.
130 p.
19. Eipper, A.N. and H.A. Gegier.
1965. Fish management York farm p'nds. Cornell Extenri-. Bull. 1089. New in New
York
State College of Agriculture '.naca, New York. 39 p.
20. Fidler, Gary. 1973. Knowledge about your fish pond.
Bureau
of Fisheries and the United States Peace Corps, Manila,
Philippines. 28 p.
21. Fijan, Nikola.
19C6. Problems in carp fish pond fertilization.
FAD World Symposium on
Warm Water Pond Fish Culture. Rome, Italy.
22. Francis, Francis.
1865. Fish culture: a practical guide to the
modern system of breeding and rearing tish. Routledge, Warne,
and Routledge. London. 320 p.
23. Fridthjof, John.
1962. Encouraging the use of protein-rich foods.
FAO, Rome, Italy. 103 p.
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of
Wisconsin Press. Madison, Wisconsin: 429-441.
25.
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about carp culture.
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Manila, Philippines. 7 p.
26.
Gray, D. Leroy. 1970. The biology of channel catfish production.
Agricultural Extension Service, Circular 535. University of
Arkansas. 16 p.
187
27. Grizzell, Roy A., Jr., Olan W. Dillon, Jr., and Edward G. Sullivan. 1969. Catfish farming - a new farm crop. Farmer's Bulletin 2244. USDA. 22 p. 28. Hara, Shiro. 1972. Experiment on induced spawning of catfish
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29. Hickling, C.F. 1961. Tropical inland fisheries. London. 287 p.
30. Hickling, C.F. 1968. The farming of fish. London. 88 p.
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188
189
190
68.
IVI
1 gram (gm) I kilogram (kg) 1 mg/l I liter (1) 1 inch (in) I foot (ft) 1 meter (m) 1 are
I hectare
o Centigrade (C)
a . a = = . -
100 eres
2.5 acres
5/9 x (F - 32)
(9/5 x OC) + 32
192
INDEX
Acclimate - p. 49
Acids - p. 15, 17, 90
Alkalinity - p. 89 - 90
Anal fin - p. 34
Anal vent - p. 34
Anchor worm - p. 168 - 169
- p. 39, 43
Bacterial diseases
p. 166
Barbels - p. 35
Barrage ponds p. 19 - 21
Black carp - p. 40, 44
Buffering ability
p. 90
Cage culture - p. 176 - 177
Calcium - p. go
Catch basin - p. 39, 45 Catla - p. 39, 45 Catt catta - p. 39, 45 Caudal fin - p. 33 Caudal peduncle - p. 33 Centrifuge - p. 143 - 145
Carbohydrates - p. 3 - 4
Carbon dioxide - p. 83 - 87
Carp - p. 2
Fish farning - p. 6
Fish nal - p. 163
Food - , 7, 100 - 106
Natura, - p. 101
Supplementary
p. 101, 117 - 119
Food quotient - p. 101 -
102
193
Fry - p. 19, 36, 110 - 113, 123 Fungal diseases - p. 165 FuundeuoiJ.4 - p. 166 Genital opening - p. 34
Genital papilla - p. 35
Gill rakers - p. 34
Gley - p. 77
Goldfish - p. 39, 50
128
Gravity - p. 17
Gytodac2tCa4 - p. 169
Hetotorr= temmnc.U - p. 40, 49 Hetoeotz nitotZicu - p. 40, 48, 139 Hormone injection - p. 141
Hybrid vigor - p. 38 - p. 49, 84, 138 Hyd~a 2Io vetticLLZt Hypophysis - p. 142
Labeo tchta - p. 40 -45 Lateral line - p. 34 LeAne - p. 168 - 169 Levee - p. 54 Level - p. 56 Lime - p. 79 - 80 Limestone - p. 80
Litmus paper - p. 89
Magnesium - p. 90
Management - p. 107 - 148
Daily - p. 115
Monthly - p. 121
Marketing - p. 152 - 153
194
Monoculture - p. 26 - 28
Monosex culture - p. 30 - 31
Mortality rate - p. 125
Mrigal - p. 39, 46
Mud carp - p. 40, 44
MyLophatungodon piceu4 -
40, 44
p.
Nets - p. 149
Nutrients - p. 3, 16 - 17, 92 - 93
Number of ponds - p. 23
Operculum - p. 34
Organic fertilizers - p. 95 - 96
0J6ph'onmu.a aoamy - p. 40, 46 - 47
Overflow channels - p. 20 - 21
Oxidation - p. 85
Oxygen - p. 14, 19, 83
88
Paddy culture - p 179
Parallel ponds - p. 22 - 23
Pectoral fins - p. 33
Pelvic fins - p. 33
Pen culture = p. 177 - 179
pH - p. 89
Phosphates - p. 99 - 100
Photosynthesis - p. 84
Phytoplankton - p. 84
Pituitary gland - p. 142
Plankton - p. 25, 36. 83 -
84
Planning - p. 11 - 52
Polyculture - p. 28 - 30, 45, 108
Poison - p. 171
Pond bottor, - p. 59
Pond prepdration - p. 79
Pond site - p. 58
Predators - p. 19, 121, 171 - 172
Preservation - p. 157
Protein - p. 3 - 5
Optimum temperatures - p. 81
Punetua gononou.O,Quicklime - p. 80
Respiration - p. 83
Rivaldi valve - p. 61 - 62
p. 47
(also
P. javaJnic.ua)
195
Rohu - p. 40, 45
Rosary ponds - p. 22
Run-off - p. 13
Salting - p. 157 - 162 SapAoen.i - p. 166 Sealing pond - p. 77 - 78 Secchi disc - p. 91 Seines - p. 150 - 151, 155 - 156 Sut~anocWmizo AbutuA - p. 166 Silt - p. 74 Siltation tank - p. 74 Silver carp - p. 2, 29, 40, 43 Siphon - p. 61 Site selection - p. 11 - 13 Size of ponds - p. 23 - 25 Slope - p. 17 - 18, 55 - 59, 77 Sluice - p. 20, 64 - 65 Smoking - p. 162 Snakeskin gourami - p. 40, 49, 138 Soft water - p. 15, 74 Soil - p. 15, 74 Spawning - p. 130 Induced - p. 130, 141 - 146
Natural - p. 130 - 140 Spoiled fish - p. 163 Springs - p. 13 Stocking - p. 107, 109 - 114 Density - p. 107
Rates - p. 108 Stripping - p. 145 - 146 Superaturation - p. 99 - 100 Surveying - p. 55 Tawes - p. 39, 47, 48, 139 Temperature - p. 81 Threespot gourami - p. 40, 4S, 138 Tilapia - p. 2, 29 - 31, 40 - 43, 109, 119, 133 ritap& macchi/. - p. 40 Tirepia me~anopteuta - p. 40 T.Zapia mos4ambica - p. 2, 40, 42 Titapia ni/otica - p. 2, 40, 42 Topography - p. 17 Trash fish - p. 163 T,%.chodina p. 168 TAichoptetu pecto at - p. 40, 49 Tichhptuuw. _tichoptvwu - p. 40, 49 Turbidity - p. 25, 90 - 92
Turn-down pipe - p. 62
134
196