Fish stocking should be arranged reasonably according to water body conditions.

During a "science and technology to the countryside" activity, the author learned that many @#@233@#@ households have had unsatisfactory yields and profits over the years in pond fish farming. The main reasons are that the fish stocked were not reasonably matched according to the feeding habits and behaviors of the fish, the varieties stocked were single, the quantities were too high or too low, and the sizes were small. This situation exists to some extent all over the country. The end of the year and the beginning of the year is the season when large quantities of fish are stocked in various places. In order to make full use of the water body, stock fish reasonably, and increase the yield per unit area of the water body, the key points for reasonably stocking fish according to local water conditions are briefly described as follows.

1. Stock fish in clear and warm weather. The stocking time for fish should be early. Generally, the water temperature for conventional fish is 5-15°C, and the water temperature for tropical fish is above 16°C. If the water temperature is low and cannot meet the requirements, it is not suitable to stock, especially in ice, freezing, snowy, windy, and rainy weather.

2. Stock high-quality large-sized fingerlings. The fingerlings are required to be robust, large, free from injury and disease, and uniform. The stocking sizes are: Pengze crucian carp or other crucian carp 50 g/fish, grass carp (old stock) 400-500 g/fish and winter fry above 200 g/fish, silver carp and bighead carp (old stock) 400-500 g/fish and winter fry above 200 g/fish, freshwater pompano 5-10 g/fish. Before the fingerlings are put into the pond, they should first be soaked and washed in 3%-4% salt water for 10-20 minutes, and then stocked to prevent the introduction of pathogens. Pond water should be used for transporting fingerlings to prevent discomfort caused by water temperature differences.

3. Stock fish reasonably. For large water areas, deep water bodies, fertile water quality, sufficient water sources, wide sources of bait, and a high level of scientific management, the method of repeated capture and repeated stocking can be used to stock more fingerlings; otherwise, stock appropriately fewer. Below is a reference ratio for stocking fish in different water bodies. ① Reservoirs. Where the water exchange volume is large and manure or fertilized water materials are applied, bighead carp should be the main species stocked, with appropriate matching of silver carp, grass carp, common carp, crucian carp, catfish, etc. Stocking large-sized fingerlings of 250-400 g gives a high survival rate. For large reservoirs with a water surface above 13.3 hectares (200 mu), stock 50-100 fish per 667 sq m (1 mu); for medium reservoirs below 13.3 hectares and above 6.67 hectares (100 mu), stock 150-200 fish per 667 sq m; for small reservoirs below 6.67 hectares, it is advisable to stock 250-300 fish per 667 sq m; for mountain ponds and drought ponds, stock large-sized fingerlings of 300-400 g/fish, about 300 fish per 667 sq m, so that they reach commercial fish standards before the autumn drought. If there are villages in the reservoir area, with much domestic sewage and nutrient-rich fertile water, 350-450 fish can be stocked per 667 sq m; reservoirs with artificial feeding can stock a little more. ② Ponds. For ponds with sufficient water sources and good conditions, rich natural bait, and artificially fed intensive ponds, silver carp, bighead carp, and crucian carp should be the main species, and 800-1000 fish per 667 sq m is advisable, among which silver carp and bighead carp account for 40%, with a ratio of 3:1 or 4:1. Crucian carp 50%, grass carp and bream 10%, with each half of that. Also stock tropical fish as a supplement (freshwater pompano or tilapia 400-500 fish). For ponds that rely on rainwater accumulation, stock appropriately fewer, with the same ratio as ponds with good water source conditions.

In short, where conditions are good, more can be stocked, and where conditions are poor, fewer should be stocked. The stocking quantity and species combination can be adjusted according to the stocking situation in previous years.