The four major fish in China are herring, grass carp, silver carp and bighead carp. Before the Tang Dynasty, carp was the most widely cultivated freshwater fish. However, because the surname of the Tang royal family is Li, the cultivation, fishing and sales of carp are prohibited. Fishermen have to engage in the production of other varieties, which has produced four major fish: herring, grass carp, silver carp and bighead carp. Mixed feeding of four major fishes can improve the utilization rate of bait and increase the yield of fish.