A Pacific salmonid with a vivid pink stripe, the workhorse of trout hatcheries worldwide.
Where it lives
Native to cold rivers and lakes from Alaska down the Pacific coast to Mexico and across Kamchatka, rainbows have been stocked on every continent except Antarctica. They favor well-oxygenated, cool water below 21 C. Sea-run forms — steelhead — migrate to the ocean and return to spawn.
How to recognise it
A silvery body marked with profuse black spots over the back, dorsal fin, and tail, with a broad iridescent pink-to-crimson stripe along the lateral line. The body is more streamlined than a brown trout’s, and the spotting extends onto the caudal fin.
Diet & behavior
Opportunistic feeders that drift-feed in current and cruise still water for emerging insects, small fish, and crustaceans. Stream rainbows spawn in spring on gravel riffles; steelhead may spawn more than once, unlike Pacific salmon. Growth in hatchery conditions is fast and efficient.
Fisheries & Conservation
Globally Least Concern. Hatchery production for stocking and aquaculture is enormous; some native steelhead populations are federally listed in parts of the United States.