Detailed Explanation of Key Technical Points for Autumn Fingerling Cultivation

Autumn water temperature fluctuates between 20-30°C, making it a good period for fish growth, especially for smaller-sized and weaker fingerlings, as this is the fattening season. Farmers must effectively strengthen fingerling cultivation.

1. Disinfect and clear the pond, transfer to a new pond: Old fish ponds used for fingerling cultivation, after several months of feeding through spring and summer, gradually experience aging water quality, reduced dissolved oxygen and food organisms, and increased pathogenic microorganisms, which will cause stagnation of fingerling growth. Grass carp fingerlings are more susceptible to disease in such old ponds. At this time, fingerlings should be transferred to new ponds for intensive cultivation. In areas lacking water sources, the water from the original fish pond can be used, and after several rounds of netting to remove all fingerlings, 30-40 kg of quicklime per mu can be used for disinfection. After fertilizing the water quality by conventional methods, fingerlings can be stocked.

2. Classify by size, reasonably match species: Fingerlings of different sizes should be stocked separately in different ponds, and different species should be reasonably matched. For example, if silver carp and bighead carp fingerlings are the main species, 30% grass carp fingerlings can be added; if grass carp fingerlings are the main species, 30% silver carp and bighead carp fingerlings can be added. The ratio of silver carp to bighead carp should preferably be 5:1. If the bighead carp fingerlings are small in size, the proportion can be further reduced, otherwise they will not grow large. For ponds cultivating three types of fingerlings, the stocking density should not be too high. Generally, for a pond with a water depth of about 1.5 m, 3000-5000 fish per mu is appropriate.

3. Strengthen feeding, fertilize reasonably: For fish ponds mainly cultivating silver carp and bighead carp, more fertilizer should be applied to ensure appropriate water fertility, and some concentrated feed should be appropriately added. Human or livestock manure or chemical fertilizer can be applied every 2-3 days. Each time, about 50 kg of wet manure is splashed, and chemical fertilizer is mixed in a nitrogen, phosphorus, potassium ratio of 1:1:0.5, with a total of 5-8 kg per mu, dissolved in water and evenly splashed. Concentrated feed should be fed at about 9:00 AM and 4:00 PM each day, with 0.25-0.5 kg of wheat bran, rice bran, soybean cake, etc. per thousand fingerlings each time. For fish ponds mainly cultivating grass carp, feeding should be strengthened. First feed green feed such as duckweed, water grass, land grass, or grass pulp, then feed concentrated feed, to avoid grass carp competing with silver carp and bighead carp for concentrated feed.

4. Scientific management, prevent fish diseases: Persist in patrolling the pond every day, observing the feeding and activity of the fish. Pay attention to water quality changes, frequently exchange with new water, generally once a week, exchanging 10-15 cm each time. For fish ponds mainly cultivating grass carp, it is even more important to keep the water quality fresh, promptly remove residual debris and leftover bait, frequently scrub the feeding platform, and disinfect the feeding platform with bleaching powder about every half month. Regularly hang baskets and bags with bleaching powder, copper sulfate, and other drugs around the feeding area to prevent fish diseases. If fish diseases or dead fish are found, promptly remove them for examination and use drugs for prevention and treatment.