Steelhead trout belong to the family Salmonidae which includes all salmon, trout, and the char. Steelhead are the anadromous form of rainbow trout which migrate to the oceans during their adult life, they then return to the same steam and rivers where they migrated from as juveniles. They are a salmonid species native to western North America and the Pacific Coast of Asia.
The term anadromous refers to fish species born in the stream that migrate to the ocean for their adult phase. Steelheads have a life cycle similar to the Pacific salmon and require the same ecological requirements.