Among them, there are more than 0/000 species of freshwater fish/kloc-,632 species of Cypriniformes, 84 species of Silurus, 56 species of Perciformes, 22 species of Salmoniformes and only 7 species of sturgeons. The skin of most fish consists of epidermis and dermis, and the epidermis is particularly thin and consists of multiple layers of cells.

The skin of most fish consists of epidermis and dermis, but the epidermis is very thin, mainly composed of countless layers of epithelial cells and mucus layers; Below the epidermis is the dermis, which is rich in blood vessels, nerves, skin receptors and connective tissue, as well as pigment cells, luster cells and fat cells.