What key steps should be taken for autumn fish fry management

Pond clearing. Transfer the fish fry to a pond that has been cleared and disinfected for rearing. If water sources and pond rotation are difficult, all the fish fry can be transferred out for temporary holding, then the original pond disinfected with 75 kg to 100 kg of quicklime per mu, and the water fertilized by conventional methods; after the chemical effect has dissipated, transfer the fish fry back.

Separate rearing. Adjust and separate the fish fry by different sizes so that the fry stocked in the same pond are of uniform size. Larger fry have a big appetite and a strong ability to compete for food; if small-sized fry are stocked in the same pond, the small fish will decline in condition because they cannot get enough feed. Fry over 16 cm can be put into adult fish ponds for supplementary stocking, while smaller fry need to be reared in dedicated ponds.

Sparse stocking. In autumn, fish fry should be stocked sparsely and rationally according to conditions such as water surface size and water depth, so as to promote fry growth and increase the overwintering survival rate. Generally, for a pond with a water depth of 1.5 m, stock 4000 to 6000 fry of 7 cm to 8 cm per mu, and by the end of the year they can reach a body length of 13 cm to 17 cm.

Feeding. In autumn the temperature is stable, the water temperature varies little between day and night, and the fish fry have a large food intake and grow rapidly, so feed supply must be ensured. For fry ponds mainly containing herbivorous fish and supplemented with silver carp and bighead carp, green feed should be the main feed, with an appropriate amount of concentrate; feed 1.5 kg to 2.5 kg of small duckweed per 10,000 grass carp fry per day. Feed green feed first, then concentrate, to avoid grass carp competing with other fish for food. Feeding should ensure quality, a fixed amount, fixed times and fixed locations. Fry ponds with mixed silver carp and bighead carp must be fertilized regularly, once every 10 to 15 days, applying 70 kg to 90 kg of fermented human and livestock manure per mu, and keeping the pond water transparency at 30 cm to 35 cm. For fry ponds mainly containing silver carp and bighead carp and supplemented with grass carp, fertilization should be the main method and feeding supplementary; besides applying base fertilizer, apply topdressing once every 5 to 10 days, applying 80 kg to 100 kg of decomposed human and livestock manure per mu. At the same time, feed 2 kg to 4 kg of concentrate per 10,000 fry per day; for the supplemented grass carp, before feeding concentrate, feed 60 kg to 90 kg of green feed per 10,000 grass carp.

Pond inspection. During the fry rearing period, inspect the pond every day to observe the fish's feeding and living conditions, and add or change new water once a week. Clean the feeding area frequently, promptly remove residual scraps and leftover bait, and every half month disinfect around the feeding area by splashing 0.5 kg of bleaching powder mixed with water. Regularly feed medicated bait, preferably twice a month, for 3 consecutive days each time.