Feeding and Harvesting in Composite Fish Culture

Feeding:

• With the increase in the carrying capacity of the pond either by aeration of water or by supplying the supplementary feed, fish growth can be augmented further.
• For getting very high production, fishes are fed with protein rich feed. Usually the conversion coefficient is 1: 2 i.e. 2 Kg of feed is given for every 1 Kg of fish yield. With supplementary feeds such as rice bran and oilcake, the fishes grow 10 times more.
• The Grass carp are normally feed tender aquatic weeds like Najas, Hydrilla, Ceratophyllum and Chara, forage grasses or chopped green cattle fodders like Napier grass, Barseem, maize leaves, etc and kitchen vegetable refuse.
• The cattle fodder is grown on the terraced embankment of the pond.
• They are fed twice at the rate of 100 Kg / ha in the first month and the quantum is increased by 100 Kg / month at fortnightly or monthly intervals, till the end of harvesting.
• The food of grass carp is normally placed on a floating frame made of bamboo poles.

Harvesting and Yield:

• Harvesting of fish is generally advocated after one year of rearing.
• Shorter rearing periods may also be resorted depending on the pond conditions and size of the fish prefered in the local markets.
• An individual fish grows to the size of 0.8-1Kg in 12 months. Grass carp have a faster growth rate and attains a size of 3 Kg weight in a year. It contributes to about 30% of the total fish production of a pond.
• Random sampling is done once a month to check the growth of the fish. It also helps in timely detection of parasitic infection if any.
• Netting also helps in raking the pond bottom which results in the release of obnoxious gases from the pond bottom as well as release of nutrients from the bottom soil.