The shortage of natural food in ponds under high density culture conditions requires supplementary feeding. Indian major carp are fed supplementary diets using combinations of a number of conventional feedstuffs such as rice bran, various de-oiled seed cakes, fishmeal, etc. (Table 7).
A mixture of finely powdered groundnut/mustard oilcake and rice bran/polish, in equal proportions by weight, is provided for larval rearing in the nursery ponds. Alternative feeds are mixtures of powdered aquatic insects, prawn and cow peas, fishmeal and groundnut oilcake. Feed is normally spread over the pond once daily in the morning (CIFRI, 1985a).
In fingerling rearing ponds, a mixture of groundnut or mustard oilcake and rice bran (1:1) is supplied to the fry in the morning (CIFRI, 1985a).
Under polyculture conditions with other Indian major carps at densities between 15 000 and 35 000/ha the fish are fed with a mixture of rice bran and groundnut oil cake (1:1) at the rate of 10, 8, 6 and 4 percent of mean body weight during the 1st, 2nd, 3rd and 4th months, respectively (Mohanty, 2002). The addition of other ingredients such as fishmeal, soybean flour and vitamin-mineral mixture is also recommended to improve the quality of the fry feed (ICAR, 2006).
The most commonly used food in grow-out ponds is a mixture of mustard or groundnut oilseed cake and rice bran or rice polish (1:1) and fed at a rate of 2-3 percent of fish biomass per day (CIFRI, 1985b, Sen and Chakrabarty, 1985). Various items of plant and animal origin are also used as food for catla such as leaves, grasses, tubers, roots, starches, oilcakes, grain fodders and other agricultural by-products. Commonly used feedstuffs of animal origin are chironomids, fishmeal, prawn meal, silkworm pupae, etc. Size specific feeding regimes for catla are summarized in Table 8.
