1. Appearance: blackfish usually have a black or dark brown body, a long and laterally flattened body, and a slightly forked tail. They have well-developed jaws and tiny gill rakers. While the catfish's body color is relatively bright, common catfish species such as the Chinese catfish, the body color is silvery white or light yellow, the body is more rounded and fat, there is no obvious tail fork like the blackfish.

2, habits: blackfish mainly inhabits in freshwater environments, such as rivers, lakes and ponds. They are carnivorous fish, feeding on small fish, crustaceans and other invertebrates. Blackfish migrate upstream to spawn during the breeding season. Catfish are also freshwater fishes commonly found in rivers, lakes and floodplains. They are omnivorous fish, feeding on benthic organisms, plankton, plants, etc.

3. Distribution: blackfish are distributed all over the world, including Asia, Europe and North America and other regions. While catfish is mainly distributed in freshwater systems in Asia and Europe, especially in China, Russia, Ukraine and other countries.