While the average size of rainbow trout is 15 to 25 inches and 1 to 5lb, this trout species can reach a maximum size of around 40 inches and 35-40lb. Some genetically altered stocks can even produce fish that weigh close to 50lb.
While the average size of steelhead is 20 to 30 inches and 4 to 10lb, this trout species can reach a maximum length of around 45 inches and a maximum weight of about 40lb.
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.