Rainbow trout are colorful fish. Their bodies are blue-green or yellow-green. They have a rose-colored strip along each side of their bodies. Their underbellies are white. They have tiny black spots, too. The body of a rainbow trout looks like a small torpedo. The average rainbow trout is 20 to 30 inches long. The average rainbow trout weighs about eight pounds.
Rainbow trout live naturally in mountain streams, rivers, and lakes in western and northern North America. Sometimes rainbow trout migrate to the ocean. This migration makes them change to a gray color. This gray fish is called a steelhead.