Tangren, fish and wild ones are not recommended to eat. The scientific name is Silurus beardus, also known as Tangjiao fish. Taxonomically, it belongs to Siluriformes, Siluridae. It belongs to tropical and subtropical fish, distributed in all parts of southern China. There are two common species in China: local pond catfish (catfish with beard) and Egyptian pond catfish (catfish with leather beard and catfish with beard).

Tangren (local bearded catfish) has eight beards, four above and below. Yellow body color, slow growth of wild fish, generally less than 1 kg, high nutritional value and good taste. It can be cultivated artificially and has great market potential. Most of the unmanned pond fish live in sewage environment, such as sewers, and have strong vitality, and can also reproduce in fecal water.

Egyptian pond catfish (Silurus meridionalis) was introduced from Egypt. Eight beards, black all over, huge individual. Most of them are cultivated artificially, and the growth rate is very fast, and they can weigh up to 2 kilograms a year, and the largest individual can reach more than 10 kilograms. It has low requirements for living water quality and is resistant to hypoxia. The meat quality is not very good and the market price is cheap. However, it is easy to breed, its growth rate is fast, and many people breed it.