Polyculture Stocking & Fill the Whole Water Column

Total fingerlings = pond area × the stocking density per unit area. The total is then split among the species by the percentages you set — catla, rohu and mrigal — so each count is the total times that species' share. The figures come straight from the area, the density and the ratio you choose.

Because they feed at different depths and so share the pond without competing. Catla is a surface feeder taking plankton near the top, rohu is a column feeder working the middle water, and mrigal is a bottom feeder grazing the pond floor. Stocking all three uses the whole water column and the natural food in it, lifting total yield from one pond.

It is raising several compatible species together so the pond's food at every depth is harvested. The classic Indian major carp polyculture combines catla, rohu and mrigal, sometimes with other carps. Because the species occupy different niches they add up rather than compete, which is why composite culture out-yields stocking a single species.

A common starting point spreads the stock across surface, column and bottom feeders so each layer is used, but the exact split depends on your market, pond fertility and management. There is no single right ratio — set the percentages you want and the tool gives the counts. Just make sure they add to 100%.

Density depends on whether the pond relies on natural food, supplementary feed or full feeding and aeration — more inputs support more fish. A naturally fed pond stocks lighter than an intensively managed one. Use the density your management and water quality can sustain; the tool turns it and the area into fingerling numbers.

Too many fish for the pond's food and oxygen means slow, uneven growth, stress, poorer water quality and higher risk of disease and kills. Stocking density has to match what the pond and your feeding and aeration can support. The calculator helps you set a number you can actually grow out.

Because it is what makes polyculture pay. If all the fish fed at one depth they would compete for the same food and the rest of the water column would go to waste. By matching surface, column and bottom feeders to their layers you harvest plankton, suspended matter and bottom detritus all at once from the same pond.

Yes — common carp, grass carp or silver carp are often added to a major-carp pond to use extra niches such as bottom detritus or aquatic weeds. This tool focuses on the catla, rohu and mrigal split; if you stock more species, set their shares within your overall ratio and adjust the percentages accordingly.

They are accurate for the area, density and ratio you enter. Real stocking should also reflect water quality, expected survival, feeding and your target harvest size, so treat the counts as a plan. Order a few extra fingerlings to cover mortality, and refine the density against how the pond performs.