The steelhead has the same general appearance as other rainbow trout, particularly when young. The adult has a streamlined, torpedo-like body shape. When fresh from the sea, they are usually very bright silver. As they approach spawning a pink to red lateral line appears that extends over the gill covers then gradually they darken to a dull grey or brown.
They can be found in rivers and streams draining to the Pacific Ocean all the way from southern California to the Alaska Peninsula and all of Vancouver Island. They are a rainbow trout that spends some of its youth in freshwater, migrates to the sea, then returns to freshwater to spawn. They make long marine migrations into the North Pacific area.
Young eat invertebrates like crustaceans, insects, caddisflies and black flies. They will also eat salmon eggs when available. At sea, they feed primarily on fish, squid, and amphipods.
Steelhead can live up to nine years and they spend up to three years in freshwater before heading to sea. After spawning, many adult steelhead returns to the sea and some (up to 20 percent, mostly females) return to freshwater after recuperation to spawn a second time. Some individuals can spawn many times and those that repeat spawn are referred to as kelts. Normally two or more summers are spent in the Pacific Ocean before the steelhead return to seek their spawning streams at the age of four or five.
Young steelhead is brightly colored with tints of red, green-yellow, orange and gold. As they mature they more closely resemble the Atlantic salmon in structure and appearance with heavier spotting. When in the sea the body is mainly silver with a blue back. At spawning time, a band of red color develops along each side of the body.