The family Salmonidae includes whitefish, trout and salmon. There are 68 species in this family. Not all trout are closely related. Atlantic salmon and brown trout are classified together in the genus Salmo, Pacific salmon and rainbow trout are classified together in the genus Oncorhynchus, and brook and lake trout are classified together in Salvelinus. Young trout hatch in spring. At first they feed on plankton, then insects and crustaceans, and add fish and amphibians when they are mature.

Brook trout spawn in Autumn. Females can carry seven thousand eggs and deposit them in multiple nests which the males then guard. While most are under 14 inches in length, they can reach 31 inches and 14 pounds.

Lake trout are the only trout which do not lay eggs in streams, preferring deep lakes. Females can carry up to 8 thousand eggs. While most weigh between 2 to 10 pounds some have weighed more than 40.

Brown trout can live 10 years and reach more than 20 pounds.

Female rainbow trout can carry 3 thousand eggs. They can live 6 to 7 years and reach a record of 26 pounds.