Catfish are mainly divided into leatherbearded catfish, pond fish, native catfish and catfish. Leather bearded catfish: because it was introduced from Egypt, it is also called Egyptian bearded catfish and Egyptian pond fish. It has eight beards, and its whole body is gray-black, with fins on its back and abdomen. Among them, there is a thorn in the back fin, which is relatively large in size and long in head, and has low requirements on water quality and poor meat quality. Tangjiao fish, also known as Silurus meridionalis, is mostly distributed in southern China. It has eight beards, four on the top and four on the bottom, dark yellow all over, relatively small in size, high in water quality and good in taste, so it is more expensive in the market. Silurus asotus is distributed all over the country, with four beards, long on the top and short on the bottom, dark yellow on the whole body, carnivorous, mostly wild, spotted on the body, small in size and low in water quality requirements; Silurus meridionalis is mainly distributed in the south of the Yangtze River. Its appearance is similar to that of Silurus meridionalis, and it has four whiskers. However, Silurus meridionalis has a particularly large mouth and is much bigger than Silurus meridionalis.