Detailed Explanation of Key Technical Points for Autumn Fish Fry Cultivation

Autumn water temperatures are suitable, making it a great season for rapid growth of fish fry. Doing a good job of autumn fish fry cultivation is crucial. The key technical points for autumn fish fry cultivation are as follows:

1. Pond clearing

After 2-3 months of fish fry cultivation, pond water quality deteriorates, natural food decreases, and harmful substances and pathogenic bacteria increase. Therefore, after the beginning of autumn, fish fry should be transferred to ponds that have been cleared and disinfected for cultivation. Under conditions where water sources and fish ponds are relatively insufficient, all fish fry can be transferred out for temporary holding, and the original fish fry pond can be disinfected with 75-100 kg of quicklime per mu. Fertilize the water quality by conventional methods, and transfer the fish fry back after the medicinal effect has dissipated.

2. Separate rearing

Larger fish fry have a big appetite and strong ability to compete for food. If smaller fish fry are stocked at the same time, the smaller ones will decline in condition because they cannot get enough food. Fish fry over 16 cm can be put into adult fish ponds for supplementary rearing, while smaller fish fry should be cultivated in dedicated ponds.

3. Sparse stocking

Carry out reasonable sparse stocking according to water surface size, water depth, and water source conditions to promote fish fry growth. Generally, for a pond with a water depth of 1.5 m, stock 4000-6000 fry of 7-8 cm per mu. After rearing until the end of the year, body length can reach 13-16 cm.

4. Feeding

In fish fry ponds mainly raising herbivorous fish fry with silver carp and bighead carp as companion species, mainly feed green fodder and appropriately feed concentrated feed. Each day for every 10,000 grass carp fry, feed 80-100 kg of small duckweed, tender upland grass, or aquatic plants, and 1.5-2.5 kg of concentrated feed. Feed green fodder first to avoid grass carp competing with other fish for food. For fish fry ponds with mixed rearing of silver carp and bighead carp, regular fertilization is required. Every 10-15 days, apply 80-120 kg of fermented human and livestock manure per mu. Keep pond water transparency at 30-35 cm. In fish fry ponds mainly raising silver carp and bighead carp with grass carp as companion species, fertilization should be the main method and feeding supplementary. In addition to applying base fertilizer, apply topdressing once every 5-10 days, with 80-120 kg of decomposed human and livestock manure per mu; each day for every 10,000 fish fry, feed 2-4 kg of concentrated feed. For the companion grass carp, before feeding concentrated feed, feed 80-100 kg of green fodder per 10,000 grass carp. Keep pond water transparency at 25-30 cm.

5. Pond patrol

During fish fry cultivation, persist in patrolling the pond every day, observe the feeding and activity of the pond fish, pay attention to changes in water quality, frequently replace with new water, and add new water once a week. The feeding grounds should be cleaned, and leftover feed and grass residues should be removed in time. Every half month, splash 0.5 kg of bleaching powder dissolved in water around the feeding grounds, or use other drugs in hanging baskets or bags. Medicated feed can also be fed regularly, preferably once every half month, for 3 consecutive days each time. If diseased fish are found, diagnose and treat them promptly.