Trout is one of the most difficult fish to classify because of its irregular physiological structure and great differences in body color and habits. In addition, artificial breeding, hybridization and the introduction of foreign varieties make the classification of trout more complex. There are several trout originally classified as trout. It is generally believed that trout should be classified as salmon.
Brown trout is the only trout classified as spot trout, and it is also an endangered animal among trout. Trout of the genus Salmo includes stream trout, lake trout and sea trout, while salmon includes rainbow trout, mountain trout and golden trout. Because trout is an ideal fishing and food species for many people, a large number of trout will be caught all over the world every year. Therefore, at present, the number of most wild mountain sea trout, mountain trout and other trout in the world has decreased sharply and is endangered.