number of species of freshwater fish

A trout is a kind of teleost fish that belongs to the Salmoninae subfamily of the Salmonidae family. There are many different kinds of trout. They belong to the same family as the salmon.

Rainbow trout
Biwa trout

Most trouts are fresh water fish. They live in clear streams, rivers and lakes in America, Europe, and Asia.

To distinguish a trout from other species, look for a second dorsal fin (or adipose fin). Also, look for spots in mature trout and parr marks in the young.