The fingerling rearing pond, like the nursery pond, should be free from weeds and predators. Submerged weeds and predators are killed by mahua oilcake (which is toxic for three weeks), which then acts as a good fertiliser, giving a rich crop of zooplankton which is good for catla in rearing ponds.
If there are no weeds, to kill predators and competitors quickly you can just add 100 kg of urea followed 24 hours later by 200 kg of fresh bleaching powder (which is toxic for only a week) for a 1-ha area of a 1-m deep pond. Fish killed in this way can be eaten.
A week after treatment with bleaching powder, add fresh cow dung (2,500 kg/ha) or a mixture of cow dung (2,500 kg/ha) and poultry manure (1,250 kg/ha). If mahua oilcake is used, no fertiliser need be added for the first 15 days.
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