How to save feed in yellow catfish farming? Practical tips shared

Currently, yellow catfish farming is fairly widespread and is a major farmed species for increasing income among fish farmers in many places. However, during the farming process, many farmers, in a one-sided pursuit of output, do not know how to save feed and continuously put too much feed and fertilizer into the aquaculture water. This not only makes farming costs rise day by day, but also causes the water quality to deteriorate continuously, affecting the growth of yellow catfish and leading to low farming benefits. How can feed costs be saved in production practice?

Strictly remove trash fish and carry out pond clearing and disinfection. Pond clearing and disinfection can both kill wild trash fish, reducing competitors for food, and kill disease-causing agents in the water, improving water quality and giving yellow catfish a good environment for feeding and growth. If there are many wild trash fish and miscellaneous shrimp in the pond, they will compete with yellow catfish for bait, and ferocious fish may even prey on yellow catfish, reducing feed utilization, so attention should be paid to removing them.

Before stocking fry and fingerlings, both new and old ponds must be cleaned and disinfected. Old ponds should have excess silt removed, keeping only 10 cm of bottom mud. 10 to 15 days before stocking fingerlings, use drugs to clear and disinfect the pond in order to kill pathogens and harmful organisms in the aquaculture water. Generally, two methods can be used: dry pond clearing or clearing with water present. For dry pond clearing, about 75 kg of quicklime per mu or 4 kg to 5 kg of bleaching powder can be used; for clearing with water present, about 150 kg of quicklime per mu can be spread over the whole pond, and the bottom soil should be mixed with the quicklime as much as possible, so as to thoroughly kill parasites, pathogens and wild trash fish, reduce food competitors and improve feed utilization. Pond farming of yellow catfish requires relatively deep water, abundant water sources, good water quality, and the ability to drain and irrigate, so ponds with an area of 2 mu to 5 mu should be chosen, with a stable and sufficient unpolluted water source, and the water quality must meet aquaculture water standards. The pond should have convenient inlet and drainage, and a flat bottom, and should be able to maintain a water depth of 1.5 m to 2 m, because if the water is not deep enough and light is too strong, it is not suitable for the habit of yellow catfish feeding under weak light. Before stocking fingerlings, sufficient base fertilizer should be applied. Generally, fermented organic manure is used to fertilize the water, at 150 kg to 200 kg per mu, and fingerlings are stocked after large numbers of zooplankton appear in the pond water.

Pay attention to reasonable stocking. A reasonable stocking density can improve feed utilization; suitable matching species can make full use of feed, coexist mutually beneficially, achieve harmony in the water body and improve feed use efficiency. To achieve a high survival rate in yellow catfish farming and reduce feed waste, stocking density and companion fish species must be well controlled. When stocking fingerlings, large-sized fingerlings of about 30 g each should be selected for grow-out rearing. The stocking quantity of fingerlings can be flexibly controlled according to pond conditions, management level, feed supply and fingerling size. The stocking density should be as appropriate as possible: too sparse means the pond is not fully utilized and benefits are low, while too dense means fish grow slowly and disease is induced. Matching should be reasonable, with the premise of fully using the water layer space of the pond and not competing for food. Generally, about 1,500 yellow catfish fingerlings of 30 g each can be stocked per mu, and about 200 silver carp and bighead carp of 50 g each can also be matched. The stocked fingerlings should be neat in size, bright in color, smooth in body surface, free of disease and injury, with intact fins and strong physique, and should be soaked in 5% salt water for 10 minutes before entering the pond. Yellow catfish fingerlings are generally stocked in late April each year, and the matched silver carp and bighead carp should be stocked half a month after yellow catfish enter the pond, so as to benefit the growth of yellow catfish. In addition, as the fish continue to grow, in order to adjust the farming density and improve benefits, they can be harvested and marketed in batches and subjected to rotational harvesting and stocking, so as to adjust the fish-carrying capacity in the water and improve the feed return rate.

Scientific fertilization and feeding. The amount of farming inputs such as fertilizer and bait affects both the growth of yellow catfish and changes in water quality. In natural waters, the food of yellow catfish is mainly small shrimp, fish and fish eggs and some aquatic insects, aquatic plants, etc. Therefore, artificial farming can use fresh live animal bait such as small fish and shrimp, and scraps from livestock and poultry processing, and can also feed soybean cake, peanut cake, bran, etc. Generally, self-made compound bait is mostly used for domestication feeding. The bait is made by mixing imported fish meal, meat and bone meal, blood meal, soybean meal, rapeseed meal, dried fish worms, etc. with feed additives. In the early stage, the protein content is above 35% to 45%, and the crude fat content is 5% to 8%; in the later stage, small miscellaneous fish meal can replace part of the imported fish meal, and a protein content of 30% and fat of about 6% is sufficient. The reference formula is: fish meal 25%, soybean cake 20%, rapeseed cake 30%, wheat flour 20%, corn flour 3%, minerals 2%, vitamins 0.2%. The bait fed must be fresh, without mold or spoilage, and it is advisable to choose complete compound feed produced by regular manufacturers. During feeding, attention should be paid to grasping the principles of “domestication feeding, early feeding, and small meals more often.” Wild yellow catfish like to feed by hiding by day and coming out at night. Under artificial farming conditions, after 5 to 7 days of domestication, they can completely come to the bait table to feed during the day. Two days after fry and fingerlings enter the pond, artificial feeding domestication is adopted. During domestication, a fixed feeding signal is used to train them to feed at fixed points and fixed times. After patient domestication for 5 to 7 days, they can feed normally; domesticated fingerlings stocked in this way can be fed normally on the second day after entering the pond, and the feeding method can use either manual or mechanical feeding. Feeding should achieve early feeding and small meals more often. The whole feeding process should be divided into three stages. In the first stage, in May and June, feed 4 times a day, with a daily feeding rate of 3% to 5%; in the second stage, from July to September, feed 3 times a day, with a feeding rate of 2% to 3%; in the third stage, after October, feed 2 times a day, with a feeding rate of 2%, feeding during the period each day when dissolved oxygen is relatively high. On this basis, the feeding amount should also be adjusted according to weather and water quality conditions. In addition, because the mouth cleft of yellow catfish is relatively large, the bait particle size should be correspondingly increased, with 2 mm particle feed used as the opening feed, and the particle size of adult fish feed can reach more than 5 mm. Sinking hard pellet bait is required to remain stable in water for 15 minutes; using floating bait will better improve bait utilization.

Regularly adjust water quality. To farm fish, first cultivate water. The quality of the water affects the speed of yellow catfish growth and the feed coefficient. Yellow catfish like fresh water quality. With good water quality, they grow rapidly, have fewer diseases, can fully use bait and reduce the feed coefficient. In grow-out farming of yellow catfish, water quality management is the most critical, and a clear water environment needs to be maintained. To prevent water aging, in May and June, inject water once a month, each time replacing with 30 cm of new water; from June to September, change water once every half month, each time about 15 cm, keeping the water depth at 1.2 m to 1.5 m. Persist in regular disinfection. From June to September, use 15 ppm quicklime to spread over the whole pond once a month, to purify and disinfect the water quality and reduce excessive organic suspended matter in the water. Every half month, use 5 kg of quicklime (or 2 kg of bleaching powder) for local treatment once at the feeding site and the aerator area. Persist in observing the algal phase and algal concentration in the water body, and according to water color use inorganic fertilizer (urea, superphosphate, potassium dihydrogen phosphate, etc.) to adjust water fertility, maintaining transparency at 30 cm to 35 cm. According to dissolved oxygen measurements and weather and water quality conditions, scientifically use aerators. On sunny days, persist in running the machine for 1 hour in the early morning and in the afternoon. In rainy and stuffy weather, make full use of mechanical aeration to supplement insufficient dissolved oxygen in the water body. Dissolved oxygen should be maintained above 3 mg/L.