China is a country short of fresh water, so at present many reservoirs have become the water sources of urban water supply, and water bodies cannot be polluted. Under such conditions, it is required that the cultured varieties can not pollute the water quality, but also help to purify the water quality. Breeding varieties can't be artificially fed, so they can only use the natural bait resources of the reservoir.

According to the quantity and species of natural plankton in the reservoir, bighead carp feeding on zooplankton and silver carp feeding on phytoplankton should be generally selected for stocking (large-scale stocking or cage culture), such as plankton, small miscellaneous fish and benthos are abundant, and bighead carp and big whitebait can also be stocked together. Bighead carp can purify water and improve transparency. Big whitebait can eat small wild fish in water, reducing the consumption of oxygen and nutrition. In aquaculture, it is necessary to monitor the water quality index and fish growth at any time, adjust the stocking amount in time, truly achieve the purpose of "raising fish with water and purifying water with fish" and improve economic and ecological benefits.

The content of this article comes from "Practical Medicinal Animal Breeding Technology" published by China Agricultural Publishing House.