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 which 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.
Stocking pond of standard size is 1.0 ha area and about 2.0 to 2.5 metre of water depth.
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.
Nursery pond requires an area of 0.06 ha and 1.0 to 1.5 metre of water depth.
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.
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 metres).
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.