teelhead and rainbow trout are the same species of fish but live a much different life after hatching. A rainbow trout will stay in freshwater streams while a steelhead will leave freshwater and spend a portion of its life in saltwater until returning to its freshwater spawning grounds to breed.
While rainbow trouts are true trouts, lake trouts are actually char. Lakers have dark bodies with light spots, while rainbow trout have light bodies with dark Spots. Rainbow trout have a broad, reddish stripe along their lateral line, which lake trouts lack entirely.