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.
Most trouts are fresh water fish. They live in clear streams, rivers and lakes in America, Europe, and Asia.
It is possible to work out the difference between a trout and any other fish, by looking for a second dorsal fin (or adipose fin). Also, you can find for spots in mature trout and parr marks in the young.