Rainbow Trout

Rainbow Trout
Latin Name

Oncorhynchus mykiss

Group Name


Taxonomy details


Rainbow trout are closely related to salmon and arctic char. They exist in two different forms, a Pacific Ocean sea-run strain known as steelhead and a smaller, landlocked (freshwater) variety. The species is native to Pacific Ocean drainages from Mexico to Alaska and northeast Asia. In their natural habitat, rainbow trout prefer cold, clear water with a fast current.

Species Description

Rainbow trout have a slender, elongated body distinguished by an iridescent pink or red lateral line. They are generally silvery on their sides (sometimes with a greenish tinge in landlocked specimens), with a dark blue to olive back and a white underside. Their flanks and all of their fins (including their tail) are sprinkled with dark spots. Rainbow trout grow to about 15-40 centimetres and seldom exceed 1 kilogram in streams or 3 kilograms in lakes. There is much more food in the ocean so steelhead grow larger, typically 50 to 75 centimetres in length and four kilograms in weight. The Gerrard rainbow trout of Kootenay Lake in south-central British Columbia are famous for their large size with adults typically exceeding 10 kilograms.