The most common types of fish housing are: Earthen pond, Concrete tank and Re-circulatory system. However, depending on where you are using for your farm and the quantity you want to raise, it is possible to use some temporary form of housing for your fish.
For instance, plastic tanks with open end can be used, it is also possible to construct fish pond with very strong tarpaulin and wood popularly known as Movable ponds”. To get a detailed description of how plastics tanks and tarpaulin can be used for fish housing, the author of this post can be contacted.
Types of Ponds for Culture
Several kinds of ponds are required for fish culture, depending upon the function performed by each.
These are small tanks that are used for hatching of fertilized eggs, and are provided with continuous slow flowing water for aeration. Each tank is usually of 2.5 m x 1.25 m x 0.6 m size.
However, small cloth tanks called ‘hapas’ made of coarse cloth or mosquito curtain cloth (2.0 x 1.0 x 0.50 m) is also used for hatching and is fixed in a larger tank.
Read Also: Introduction to Fisheries / Classes of Fish
This is a small pond in which brood fish are placed for spawning. Brood fish may also be placed in hapas for spawning.
These are larger ponds for newly hatched fry. Usually it is 15 x 15 x 1.2 m and is seasonal which dries up during summer.
These are larger ponds, usually of 30 x 10 x 1.25 m, and are used for rearing advanced fry till they grow into fingerlings. They may be seasonal or perennial and have a gentle slope to facilitate netting of fingerlings.
This is a large perennial pond, more than 2 m deep and is used for the growth of fish to marketable size. The size of the pond depends upon the fish species to be cultured.
In addition to the above, 2-3 marketing ponds are also constructed in a fish farm. These are used for stocking fish ready for the market. These ponds are arranged in two or more parallel rows, with 1.25 m space separating them.
Three kinds of ponds are constructed for fish culture.
(i) Ravine pond made by claiming a dry ravine or creek,
(ii) Excavated pond is prepared by removing clay from a fairly level area. Excavation is done up to the required depth. Water supply is arranged from a nearby river, canal or well and the inlet is provided with cut off valve and screen,
(iii) Levee ponds are constructed without excavation on an agricultural land. A levee pond is like an irrigated rice field, but the pond levee is considerably higher.
Before constructing a fish farm, selection of a suitable site is important. Economy of construction and productivity of the ponds depends largely on its location.
The main consideration should be the topography, soil type and source of water. A gently sloping terrain of a valley, or a bowl shaped area with high lands on three sides and a narrow outlet on the fourth, are considered to be ideal for a fish farm, provided the soil is suitable and water supply is available.
Such an area can be easily converted into a large pond by constructing an embankment on one side to close the outlet. The soil must be impervious to the water. Rocky and sandy soils should be avoided and silty clay is preferred. If the land has been used for agriculture, soil should be tested for residual pesticides, which are toxic to fish.
Soil should be tested by a soil analyst to determine whether or not the soil is capable of holding water, especially during the dry season.
Nursery and rearing ponds can be constructed on porous soil, as they are seasonal and are required to hold water for a short period; but for stocking ponds, porous soil should be treated with clay or suitable soil-sealant is spread over the bottom in several layers to make it impervious.
Availability of adequate supply of water is an important consideration. Rivers, lakes or big reservoirs are considered to be the best source of water. Streams, canals and wells are also good and dependable source of water for the ponds.
Arrangement should be made for proper drainage. Ponds should be so constructed that each can be drained completely and individually, and water can be replaced with fresh oxygenated water.
The drain pipe of the pond should be large enough for quick drainage. The inlet pipe should be 15-20 cm above the water level, and must be provided with a screen to prevent the entry of wild fish.
A screen should be placed at the end of the outlet also to check loss of fish. Another factor to be considered is that the pond should be free from overflow or flooding from rain water.
Layout of a Fish Pond
The layout of a fish farm depends upon the total area available, species to be cultured, and the type of farming to be practiced. For restricted farming, fry and fingerlings are procured from the market, and are grown in ponds to marketable size. For this few rearing and stocking ponds are required to be constructed.
But in complete fish farming a larger number of tanks are required for specific purpose, as the brood fish are spawned, eggs are hatched, fry are reared to fingerlings and adults.
Before constructing the ponds, selected site is cleared of all the trees, stumps, rocks and stones, which are likely to interfere with netting and harvesting operations.
Ponds should be arranged in such a way as to provide maximum efficiency of production. Usually small farms (1-5 acre) are preferred as they are easy to manage, and small ponds can be drained and refilled quickly, facilitating better care of the fish.
Ponds can be arranged in one of the following ways:
(a) Ponds are constructed in a series, one behind the other, and are connected to each other. Water from the source is supplied to the ponds by a channel, and the last pond has an outlet to drain excess of water. Ponds are connected to each other and one overflows into the other.
(b) Ponds are arranged parallel to each other and have separate inlet and outlet so that water from one pond does not overflow into the other. They may be built in one or two rows. A screen is always provided near the inlet and outlet to prevent entry of wild fish, and loss of culture fish.
Swamps can also be reclaimed and converted to fish ponds. Swamps can also be used for the culture of air breathing fishes.
Read Also: Types of Fishing Methods