Fish Pond Construction
Booklet No. 520
Fisheries and Aquaculture: FACS - 6
II. Classification of Fish Ponds
III. Types of Fish Ponds
IV. Key Points in Pond Construction
V. Survey of the Location
VI. Layout of Fish Ponds
VII, Construction Details
VIII. Post Construction Operations
Fish pond is like a vessel that should hold sufficient water throughout the year for a
desired number of fish or fishes to live and grow comfortably. The main point in the construction
of a fish pond is to make sure that it remains intact for a long period of time so that it becomes a
permanent asset that will give regular income to the owner of the pond. Very often the
construction of the pond is done very carelessly or inadequately that within one year or two the
pond becomes unfit for fish rearing. Our experience shows that people are ignorant about the
various aspects of the construction of a fish pond. I am quite aware of the need for a number of
diagrams to highlight the construction details of the fish pond. However due to very high cost
they cannot be included. Besides, engineering diagrams cannot be understood by ordinary
people without the help of some technically qualified people.
Dr. K T. Chandy, Agricultural Environmental Education
The construction of fish pond involves the knowledge of variety of things like the type of
soil, the angle of retention of a particular type of soil, soil management for construction, the
interaction relationship between water and soil, the behavaior of soils under the permanently
wet and submerged conditions etc. Only then one can construct a proper fish pond which can
last many years and in which fish rearing can be practiced regularly.
Fish rearing involves supervision and regulation of reproduction, feeding, disease
control, control of the size of the fish and the stocking and maintenance of the ponds. This
means we should have the full control of the fish rearing situation in the constructed pond so
that always an optimum range of environmental condition is made available to an optimum
number of fish per unit area of the pond.
The construction of the pond should be such that there should be least amount of
seepage or leakage loss of water, safe from siltation, side collapse and filling of the pond, safe
from other predatory terrestrial and aquatic animals, tree from the possibility of flooding or
overflowing of water or drying or serious reduction of water.
The pond also to be constructed in such a way that feeding and caring of the fish,
disease control, supervision, control of inlet and outlet of water from the pond and finally the
netting and harvesting of fish becomes easy.
Fish pond can be constructed at any place where sufficient amount of water is available.
If it is fresh water then fresh water fishes can be reared, if brackish water then brackish water
fishes can be reared; if sewage and marshy type of water then air breathing type of fishes can
be reared. We can find all kinds of fishes growing in all types of water provided the pond is
capable of maintaining the water level and quality within certain range of the optimum level.
In this booklet some of the obvious aspects of the construction of the fish ponds are
II. Classification of Fish Ponds
Fish pond can be classified according to water supply, type of rearing and types of
fishes, etc. This section of the booklet is to provide the reader some general understanding of
the possible classifications of the fish ponds.
Water, being the primary medium for the fish growth and development, the first
classification of the fish pond is based on the source of water.
1. Spring water pond
The source of water is a spring at the bottom or sides of the pond or from a spring
outside the pond. Normally such springs are excellent sources of fresh water and well suited for
rearing fresh water fishes.
2. Rain water pond
As it is clear from the term, the source of water is rain water in general. However the rain
water may be collection of roof water, run off water from a catchment area.
3. Ponds supplied by river or stream
Sometimes ponds are constructed close to the river or stream and water is allowed to
flow into it through controlled inlets.
4. Rice field ponds
One of the corners or of one side the rice fields are dug into very small ponds or ditches
of suitable size and shape to rear fish as an additional source of nutrition and income, Here the
source of water to the pond is water from the rice fields. At times one of the whole rice plots are
converted into fish-ponds besides the small ponds in each rice field. During the flooded rice
growing season, the fishes swim and feed around the whole field. In order to avoid the fish
going out wire meshes are placed at the inlets as well as outlets and the bunds around are
made strong and high. At the harvest of rice the field is dried. At that time the fish accumulate
into the ditch where they can be reared for some more time till they are harvested.
5. Sewage water ponds
Often treated or untreated sewage water can be a good substratum for fish rearing. The
domestic sewage water is collected into a pond and fishes can be reared.
6. Marshy area ponds
Often marshy or low lying areas are found in many places. Such areas can be properly
modified into ponds suit- able to grow fishes.
7. Brackish water ponds
Brackish water is found near sea shores or even in certain island areas and the ponds
filled with such water obviously will be brackish water pond.
8. Under ground water pond
In these ponds water from the under ground water sources is pumped into them
periodically to supply the required amount of water.
III. Types of Fish Ponds
Based on the usages the fish ponds are categorised into breeding ponds, spawning
ponds, hatchery ponds, nursery ponds, rearing ponds and stocking ponds or storage ponds.
They are defined and described here.
1. Breeding pond
This is a small pond in which selected female and male are maintained and the
preparations which may be artificial or natural for spawning is done. Details on breeding
techniques are separately given in another booklet.
2. Spawning pond
Spawning pond is a small pond in which selected male and female fishes are allowed to
discharge their ova and sperms into the water and which adhere to some vegetation or fibrous
material provided. The ova mass discharged become jelly like in contact with water and stick to
the vegetation at some point and the rest float in water. The sperms (milt) discharged by the
male by the side of the ova mass, swim around and fertilize each ovum.
3. Hatchery ponds
The ponds in which hatching is done are called hatchery ponds. In many cases to
improve the efficiency of hatching separate ponds are maintained. The spawns from all the
spawning ponds are collected and placed in hatchery ponds and provide optimum conditions for
4. Nursery ponds
After three to four days after hatching the frys start eating. From this stage till they are
transferred to the stocking pond the frys remain in the nursery ponds. Each batch of frys can
have separate nursery ponds, for trys 4-15 days old, 15- 30 days, 30-90 days and 90-180 days
depending on the production intensity one is following. Sometimes several nursery ponds are
maintained at the same time nursing several batches of frys.
5. Rearing ponds
Literally rearing ponds are those in which the frys are reared as an intermediary between
nursery and stocking pond. The nursery stage of 90-180 days also can be considered as rearing
stage. The fishes in the rearing ponds are at the fastest growing stage which will be continued in
the stocking ponds.
6. Stocking or storage ponds
Stocking pond is the last stage pond in which fishes are grown till they are at market
size. Comparatively this is the biggest of the ponds.
For ordinary fish farmer all these types of ponds are not available nor needed. Small
enclosed arrangements within the stocking pond itself can provide facilities for breeding,
spawning, hatching, etc. The easiest arrangement is to fix proper net in the form of an inverted
box in the pond. So water level in the net is same as that in the pond. By increasing the size of
netted area one can get the advantages of breeding, spawning, hatching and rearing
operations. Finally the net is removed and the fishes are allowed to spread themselves into the
Different ponds are maintained for different purposes only when the standards of
breeding, hatching, rearing, disease control and management practices are very high.
Some other types of ponds are also possible as mentioned briefly here. Based on the
shape of the ponds we have square, rectangular, triangular, trapezoidal, irregular, circular
ponds or ponds constructed in contours.
Based on the depth of the ponds we may have deep, shallow or medium deep ponds.
Based on the type of fishes grown we can have carnivorous fish ponds or herbivorous fish
ponds. Based on the climatic conditions we have cold water ponds, ponds with water of normal
temperature or warn- water ponds as in the tropics.
Again the ponds may be single or in groups, they may be linked or separate, they may
be constructed parallel to each other or some other ways.
Based on the type of fish we can have ponds for separate fishes like rohu pond, calla
pond, carp pond, prawn pond etc.
Based on the size of the ponds we have big ponds of one acre and above or small
ponds less than one acre up to a hundredth of an acre or even a small tank of few square feet.
Based on the material of construction we can have mud ponds, concrete walled ponds,
stone or brick walled ponds, plastic layered ponds, mud walled ponds etc. Based on whether
the water is running or stagnant we can have stagnant water pond or running water pond.
Based on the trapping in of the water we can have barrage ponds, diversion ponds or pumped
IV. Key points in Pond Construction
Certain points should be kept in mind while constructing the fish ponds. Enumeration of
these points together will help the fish farmer to plan the construction of the pond in advance
and to avoid future problems. It also will help him to have more accurate financial estimates and
plan for his fish
rearing enterprise. The key points are the following.
A. The size
There should be proper size and shape for ponds used for various poses like breeding,
spawning, hatching, nursery, rearing and stocking. Often ordinary people have only one pond in
wl1ich they rear fish from the nursery stage to the selling stage. Under such conditions they
should have at least a pond size of 70 ft long, 35 ft width and 4-5 ft water depth. The ratio
between the length and width of the pond should be maintained between 2:1 to 4:1 (the width
should be less than half the length). This is to provide the fish long stretches of swimming and
feeding space and also for easy netting. Otherwise the optimum sizes of the ponds for various
commercial purposes are the following. The size of various ponds are given in relation to pond
of one hectare of stocking pond. Therefore according to the size of the stocking pond one can
calculate the size of various ponds for breeding, spawning, hatching, nursery and rearing.
1. Stocking pond or growing pond
Stocking pond of standard size is 1.0 ha area and about 2.0 to 2.5 metre of water depth.
2. Rearing pond
On the basis of the dimensions of the stocking pond already given, rearing pond needs
0.1 ha area in size and 1.5 to 2.0 metre of water depth.
3. Nursery pond
Nursery pond requires an area of 0.06 ha and 1.0 to 1.5 metre of water depth.
4. Hatchery pond
Hatchery pond could be the same as the nursery pond in the case of small scale fish
farming, but in case one wishes to be a separate pond then he can have a small pond of
convenient size about 0.03 ha area and 0.75 to 1.0 metre water depth.
5. Breeding pond
Breeding ponds could be 0.02 ha area and 0.75 to 1.00 metre water depth. Breeding
pond could be same as the hatchery pond. But if one intends to have breeding of large number
of the same type fish or different types of fishes at the commercial level then he should have
several small ponds. He can also have small pre-fabricated concrete or plastic tanks for
breeding different breeds of fish and to hatch them separately. Even small tubs of plastic and
concrete can also be used for breeding different fishes.
The above mentioned various types of ponds are required for highly specialised
breeding or large scale commercial level fingerling production and fish farming. For the ordinary
farmers who may be having only a small general purpose pond, can use the same for various
purposes by enclosing a small portion of the pond with the help of nets or using separate small
concrete or plastic tanks or tubs.
The size is given in area and therefore the proportionate length and width of the ponds
have to be calculated for each of the pond area given above. According to the land available,
one can fix length or width and then the other can be calculated. Also one has to be proficient in
the conversions of hectare into square metre or hectare into acre and to square ft. etc. (One
hectare = 10,000 sq. metre, one ha = 2.5 acres, One acre = 43560 sq ft, one acre = 4000 sq
The recommended and relative dimensions of the ponds used for various purposes are
given for the benefit of the reader and pond fish grower, so that he knows what is the optimum
relative size of the various types of ponds.
B. The sides
The sides of the pond should be made really firm and non collapsible. This is done by
various ways like giving proper slope, compacting the soil, building or lining the sides with bricks
or stones or concreting etc. A collapsed pond is like a broken vessel which cannot hold water in
C. Water retention
The pond should retain sufficient water throughout/the rearing and growing season. In
other words it should be made leak proof. This can be made by compacting the soil, puddling
the soil, adding more clay and other binding material to soil at the bottom and at the sides of the
pond. The top soil layer (up to 6-9 inches depth) should be so compacted that practically no
seepage loss is there, though compacting is a one time labourious process.
There should be proper drainage facility. We should fix a proper outlet from the pond
through which we should be able to drain the pond fully or partially at any time without allowing
the fish to come out.
The inlet brings in water into the pond. This should be constructed in such a way that silt,
leaves or other plant parts should not come into the pond. The inlet should also control the
quantity of water coming into the pond whether during flood, rain or dry season. In short, inlet
controls the quality and quantity of water coming into the pond.
The outlet could be same as drainage or separate. In a running water pond a separate
and permanent outlet is fixed besides a drain. The outlet is fixed in such a way that the fishes
from the pond should not escape. The water level in the pond is maintained and the quantity of
water flow can be controlled.
Proper bunds of about 2-2.5 ft. height and of convenient width is needed all around each
pond. These bunds serve not only as boundaries but also as passages to move around and
between ponds. The dimensions of the bunds such as length, width at the bottom and top, the
height and thickness of the bunds should be even and uniform through out the bunds. Similarly
the compactness of the bunds also should be uniform.
Proper approaches to the pond site, to each pond and to the bottom of each pond is
necessary for easy movement of people and things in the fish pond area.
I. Siltation control
There should be proper control of the silt possibly coming into the pond during the rainy
season. There should be properly constructed silt catching traps before the water enters the
J. Quality of water
The quality of the water should be maintained suitable for the fish growth, especially the
amount of dissolved oxygen content. The water also should not be acidic or alkaline but neutral
for all the fresh water fishes. But for the brackish water fishes one should ensure the brackish
water. Sometimes the water may be acidic or alkaline at the source itself due to the type of soil
and the rocks through which the water comes in. The water also should be clean and
transparent to allow sunlight to reach the bottom of the pond.
K. Natural feed production
Natural feed consisting of aquatic flora and fauna are essential for healthy fish culture.
Hence in all the fish ponds special care should be provided to generate maximum natural feed.
L. Technical know-how
In actual situations of fish rearing what is mostly lacking is technical know-how. Proper
technical knowledge backed by sufficient theoretical understanding is the brain and back bone
of fisheries. For long term fish culture, timely updating of the technical know-how is necessary
for the success of the enterprises.
V. Survey of the Location
The above mentioned points will be the main check points for surveying an area
proposed for the fish pond construction. Before constructing the pond obviously the spot
selection is done mainly based on the water availability and easiness for construction and
maintenance of the ponds. Other factors like transport, communication, availability of teed and
other requirements marketing etc. are also taken into consideration. Once these factors are
taken into consideration and a spot is selected for the construction of the pond, the type of soil,
climate and topography are studied. The type of soil refers to whether it is clay, silt or sand or
combinations of any of the two or three at varying proportions. One should also know whether
the place has a tropical, temperate or cold climate and the topography whether it is leveled,
undulated or sloping; if it is sloping what is the angle of slope. Along with this the water retention
capacity, permeability, plasticity and chemical nature (acidic or alkaline) of the soil are estimated
either scientifically or through the local peoples knowledge.
Ponds are best constructed on levelled land or in the valleys and lowest part of some
catchment areas where the water table is high. Construction of pond is easier in the clay soil
however if one has proper knowledge he can make a pond in any type of soil.
It is important to know the rain fall of the place and the seasonal and climatic variation of
the place especially the relative humidity. Because based on the relative humidity the rate of
evapo-transpiration varies. In very dry areas the water loss through the evapo-transpiration will
be very high.
Depending on the type of fish rearing practice, the specific purpose whether it is for
breeding, spawning or hatching and the size of the business are further points that could also be
included. The results of the survey are tabulated and pre- served for future reference.
A summary of the points for survey are given here.
1. Is there adequate supply of water for fish pond'?
2. Is the soil able to hold enough water in the pond'?
3. Is the land suitable, and in good shape to have a fish pond?
4. Who owns the land?
5. Is the pond area close to home?
6. Is there a market for the fish produced?
7. Are there transport and communication facilities through out the year?
8. Are there enough people to help to build and harvest the pond?
9. Can the equipments and material for the pond construction be bought, borrowed or built?
10. Can the fish be stored for few days if market is delayed?
11. Availability of fish feed: both natural and artificial?
12. Are the fertilizers available ?
13. Do people'in the area like the fish?
14. Can the people of the area afford to buy the fish?
15. What is the rainfall of the area, and what is the overflow frequency and duration'?
16. What level of fish culture technology is available locally and how many families are is having
17. What administrative and financial help can be obtained?
18. How are the by-product of fish culture like the wastes of feed, fish and aquatic weeds going
to be used?
19. Is there possibility of at least primary processing and value addition to the product?
20. What is the possibility of making the pond as a permanent asset to have regular income
VI. Layout of Fish Ponds
Layout means the location and arrangement of ponds. Fish Pond layout is a branch of
fishery engineering. The possible layout is to be studied, planned meticulously and preferably
be made into a blue print.
The layout gives the full plan of the location of the ponds and mainly takes care of the
placement of various ponds in relation to people, water flow and material movement in the pond
area. Each layout will be different and specifically planned to adjust and accommodate the
needs and the resources.
It is very difficult to lay down some general rules for layout planning. However the
necessary dimensions of length, width and depth and the points to be kept in mind in
constructing a pond (as given in section V) are to be considered while a layout plan is made.
Some of the key principles to be followed in the layout planning are mentioned here.
1. Ponds parellel to the common inlet channel: In this layout the width sides of all ponds will be
parallel to the inlet channel. The same inlet channel is used to let in as well as let out water.
This layout is used in places where rainfall is low and the ponds depend on artificially supplied
water. In this layout system the outlet is not needed. However, water in the ponds will always be
2. Ponds having inlet and outlet channels parallel on both width-sides. In this system the inlet
channel brings in water into each pond separately and also is drained out into outlet channel
separately. This type of layout is used when one has a continuous flow of water.
Both the layout systems mentioned here can be modified into such a way that water
entering the first pond after it is full, flow out into the second and then to the third and so on and
so forth as people ordinarily do for paddy cultivation. This could be called "relay layout". Among
farmers this is the most commonly followed system but it is the least preferred layout for
commercial fisheries, because in such layout maximum disease incidence and other economic
risks are inherent.
Pond width parallel to inlet channel, pond width parallel to inlet and outlet channel and
the relay type of water flow ponds are regular shaped layouts, the rest may be called irregular
The irregular type of layout do not follow any fixed pattern. Ponds of various types and
shapes are arranged in such a way that the fishery can be managed easily. The arrangement
should be such that each pond receives water from the inlet channel separately and also drains
out into outlet channel separately. In other words one should have full control of the quantity and
quality of water flowing in and out of the pond.
If possible the length-sides of all the ponds should be fixed east-west to benefit
maximum from the sun rays. Locate the watch and ward building in such a place that at least
most of the ponds are in view of the manager, the watchman or workers.
In high rainfall areas and at the valley of mountains diversion channel should be
constructed to ward off sudden onrush of rain water from the upper areas of fish pond lay-outs.
The layout also should consider the protection of pond area from wild animals, predators
and thieves. This also include wild and unwanted fishes from outside. The layout should include
facilities for feed storage and distribution, regular inspection and supervision for sample
catching, for netting and harvesting for fish.
When there are several ponds in the same line and there are several lines of ponds,
they can be arranged in series (one after another) in the same line and parallel between the
lines. If there are number of ponds for each purpose such as breeding, spawning etc, then
layout can be in blocks like nursery block and block for breeding, spawning, and hatching. We
can also have blocks of ponds in such a way that each block is having all the ponds from
breeding to stocking ponds. The exact layout pattern depends on the location, topography,
climate, water source, intensity of production and the specialization of production whether for fry
production or fish production.
VII. Construction Details
The construction details and the procedure of construction varies trom place to place
and from purpose to purpose. It is also not really possible to anticipate and plan all the details of
constructions. However certain amount of planning and procedures can be identified. They are
1. Prepare a master plan
Whether the pond is small or big, single or complex, single line or in blocks whether for
home use or for commercial purposes, a master plan should be prepared before one actually
start digging the fish pond. Decide the length, width, depth at various comers and middle of
each pond and the locations of the inlet and outlet estimate the volume of the soil to be
excavated while digging the pond or making the dikes or bunds. Estimate also the slope of the
sides depending on the type of soil.
2. Slope of the sides
Depending on the type of the soil, various possible tentative slopes can be given. For
very clayey soil we can give a slope of 1:1 to 1:1.5; for the sandy soils we should give a slope of
1:2.5 to 1:4; for the soils coming in between these two types and depending on the proportion of
the clay or sand the slope is determined. More the sand lesser the slope. Such slopes are given
when the sides are made of mud only. if the pond is deep there should be steps or platform all
around the sides for every 4 to 4.5 ft continuous sloping distance.
If the sides are constructed with brick or stone walls, then the above mentioned slopes
are not applicable. Needless to mention that it is always advantageous in the long run to
construct the sides with brick or stone fortified with cement. Because it will avoid the chances of
the formation of horizontal holes and small caves which will lead to the collapse of the sides.
Besides, vertical sides will increase the water volume of the pond. However while constructing
the sides it is better to provide as many pockets of clay as possible so that sufficient flora and
fauna can grow on these pockets to provide natural feed to the fishes. The clay pockets can be
easily prepared by the arrangement of well baked clay bricks in a honey comb fashion on all the
3. Inlet for water
The inlet for the water to the pond should be constructed in such a way that water should
come into the pond without eroding the sides nor the bottom. If there is any possibility of the silt
coming into the pond along with the water, then proper silt catching structures such as ditches,
trenches, bunds or any other suitable structures should be provided. A properly constructed
water inlet must fulfill the following conditions: (i) it must assure a regular and regulatable supply
of water to the pond; (ii) it must prevent the escape of fish, (iii) it must keep out undesirable fish
which might come in through the water fed into the pond. For this, a single or double screened
case bitters can be installed at the inlet. The inlet could be a common one for a group of ponds
or for individual ponds. The clogging of the screen by the debris etc. could be prevented by
building a small check or weir and the debris collected should be cleaned off periodically.
4. By pass
Along with the inlet there should be a by-pass to divert the excess water that could
possibly be coming into the pond during the rainy season. The depth and the size of the by-pass
channel depends on the situation of the place and the position of the pond in relation to the
incoming water and the slope of the area from which the water is coming. The by-pass can also
be constructed with bricks or stone and cement which is ideal for long term commercial fish
5. Bottom of the pond
The bottom of the pond should be made firm and leak proof. This can be done by
repeated puddling of the bottom soil mixed with clay and allowing it to settle for a week and then
again puddling it and allowing it to settle for a number of times till one find that water seepage is
almost nill. Cementing or laying bricks or tiles etc. are other types of pond bottom treatment
which of course will be very costly. It is better to make the bottom of the pond slightly sloping
towards one side or to the drainage at the bottom of the pond.
6. Drainage or outlet
Every pond should be fitted with a drainage by which we can drain out water whenever
we need. This can be done by fitting a big pipe from underneath the pond towards the lower
area outside the pond. The outside end of the pipe can be fitted with a flexible pipe which can
be fixed vertically up with its end rising high above the water level in the pond to preserve the
water in the pond and put down on the ground to drain out the water from the pond. Only at the
beginning of the outlet there should be proper screens and checks fixed so that the outlet is not
blocked either by mud or by any other materials from the pond. This is also needed to prevent
fish coming out. But this type of drain is possible only when at least one side of the pond is
lower than the bottom of the pond.
The drainage structure can be of varying types and sizes as per availability of the designs such
as sluices (an artificial channel for conducting water fitted with a gate at the upper end for
regulating the flow) and monks (monk is a device resulting from the combination of sluice and
an underground drainage pipe). Siphoning is another easy method of draining the water from
7. Screens at the inlets and outlets
One of the difficulties that arises during the management of fish ponds is the frequent
clogging of inlets and outlets. Therefore both at the inlet and outlets suitable screens or filters or
traps have to be fitted. There are several designs for this and it is better to consult an engineer
for the suitable designs. To provide details of designs to fit screens, is beyond the scope of this
booklet. For the inlet the easiest structure is to have a rectangular top-open box like tank fitted
at the inlet. The first half of the tank receive incoming water. The second half of the tank is fitted
with vertically sliding screens. These could be more than one screen in succession with
sufficient space for collection of clogging materials which can be peri- odically removed. For the
outlet the easiest way is to use siphoning into a lower area or a well from which water is
pumped out. At the beginning of the outlet one or two screens could be fitted as is seen in the
case of suction pipe of a pump set.
8. Bunds or dikes around the pond
All around the pond there should be a bund sufficiently broad enough to be used as path
to go around the pond for doing various kinds of pond management activities. The height of the
bund should be about two feet above the water level. However too high or too low bunds should
be avoided. If there are several ponds the bunds of all the ponds are linked together with
connecting paths. This will enable easy movement of the people, implements, instruments and
in some cases even vehicles. The bunds should be covered with grass to avoid soil erosion,
breakage and collapse. Selected trees could be planted around the bunds to provide partial
shading to the pond in areas where very high intensity of sun rays and summer is prevalent;
however they should not be too many to breake the bunds by sending the roots or shading
beyond 50 per cent of the area. Generally trees with tap root system should not be planted. If
there is any problem of shading, prune sufficient number of selected branches to provide sun-
light to the pond.
There should be at least one well constructed staircase leading to the bottom of the
pond in case of the small ponds. But in the case of bigger ponds several such stair cases are
needed; at least at every corner. These are essential for the efficient execution of the various
management operations such as feeding, cleaning, manuring etc. to be performed in fish
10. Office facility
As in any commercial activity in fish production also there are records and accounts to
be maintained and strict supervision and guarding of the ponds is ensured. The common
records to be maintained are the following.
i. Breeding records: which would show the date of breeding, the number and types of fish bred,
ii. Spawning records: which would show whether the spawning has been successful and
satisfactory or not;
iii. Hatching record: which would show the date of hatching, the vigour of the fishlings hatched,
whether hatching is satisfactory or not;
iv. Nursery record: which will note the date of introduction of fishlings into the nursery pond, rate
and the amount of feeding, the rate of growth in the nursery pond etc.;
v. Stocking record: which will show the date of introduction of fingerlings into the stocking pond,
feeding rate, growth rate etc.
vi. Records of daily operations, special operations, disease control measures etc. Harvesting
records include date of harvesting, total yield, yield per unit area etc.
Office is also necessary to receive visitors and customers coming to the pond site. In
commercial farms communication facilities like phones and fax may be also fitted. There should
be electricity or other sources of power. Even for a home level fish pond a small office with
electricity and other essential facilities is useful.
11. Storage facility
Whether the fish pond is big or small, for commercial or home level consumption,
adequate storage facilities at the site are necessary. Facilities are required for storing feed,
implements and instruments, nets, baskets, weighing balance etc. Some times we may have to
store harvested fish for few hours at the farm before that can be lifted to the market.
A commercial fish farmer should ensure that there is link road from the farm to the public
road so that things required ; for the fish farm as well as things from the farm can be transported
easily up and down.
VIII. Post Construction Operations
After the physical construction of fish pond, it is also important to test the ponds for their
utility. Thus the utility test also is part of the construction programme. The utility tests include
filling the ponds, testing of the inlets and outlets, neutralization of pond water and fertilizer
application to the pond. These points are briefly explained here.
1. Filling the pond
Filling of the pond with water should be done only after ensuring that all the construction
details are completed satisfactorily especially the inlets, by pass, silt traps and the out- lets are
functioning well. Water is introduced gradually raising the heights in each pond as already
planned depending on the purpose of the pond whether for breeding, spawning, hatching,
nursery raising, rearing or stocking. After filling to the desired height leave the ponds for few
days to check if there is any problem arising. Care should be taken to provide the type of water
required whether fresh water or saline water or cold water according to the type of fish culture
planned in the pond. Needless to say that if there is any defect it should be rectified before one
starts using the ponds.
2. Testing inlets and outlets
The inlets and outlets are probably the most important part of a fish pond system
because it is through these that we control the water level, the inflow of desirable and
undesirable water, the quality of water in the pond, safety of fish in the pond and prevent silt
flow and muddy water during rainy season. The test also would include checking the
effectiveness of the methods used for prevention of clogging the inlets and outlets.
3. Fertilizer application in ponds
Once the water is impounded in the ponds the next stage is to leave it for natural
generation of pond or aquatic flora and fauna. Under the warm climate within few days micro
flora starts growing followed by micro fauna. This microbial growth can be increased by the
addition of cow dung, pig dung or any other animal dung. However poultry dung will be too
much heat generating and hence it should be added only after it is decomposed. Normally 0.5 to
1.5 kilogram of animal dung per square metre area could be added to fertilize the pond.
It is better to use the well rotten animal dung instead of fresh dung. If fresh dung is used,
during the decomposition large amount of heat is produced as well as till the decomposition is
over (nearly 1 to 1.5 months) the nutrients will not be available or very little will be available to
the micro flora. Secondly, during the decomposition the oxygen content in the water goes down
due to heat generation and organic decomposition below the required minimum amount 4
mg/litre ( 4 ppm) of water. It is to be noted that the amount of oxygen dissolved in water reduces
from 9.79 to 7.48 ppm when the temperature of the water rises from 15 to 30 degree centi-
4. Neutralization of water
The optimum pH of the water in the fish pond for the optimum growth of the fishes is
between 6.5 to 9.0. If the pH i is low then add sufficient lime to bring up the pH. The amount of
lime to be added in relation to pH is given here: for pH between 4-5 add 2000 kg of lime per
hectare area of pond; for pH 5 to 6.5 add 1000 kg, for 6.5 to 7.5 pH add 500 add for pH 7.5-8.5
add 200 kg of lime per hectare of pond area. If the pH is very high then application of gypsum at
the rate of about 200 kg per hectare can bring down the pH. Mildly alkaline water can be turned
to neutral by the heavy application of organic manures and leaving the pond for a month.
The fish ponds and other infrastructural facilities for fish farming should set up in such a
way that they become a permanent asset which can generate regular income to the owner or to
cultivator. They should be one time capital in- vestments which should help in regular culturing
and harvesting of the fish for many years to come. Even a home level fish pond should be
constructed in such a way that it becomes a permanent asset to the family to get a regular
amount of income. A well established fish pond system is perhaps the most profitable farm