Is there a more beautiful or popular fish? Depicted on corporate logos, ball caps, and gas station signs, the rainbow trout is the ideal symbol combining beauty and sport. Rainbow trout (Oncorhynchus mykiss) is favored by fly fishers because of its beautiful coloration—for which it’s named—and its fighting ability. Wild rainbow trout typically have olive-colored backs, tails peppered with dark spots, and silvery sides that look as if they’ve been painted pink and crimson.
The rainbow trout is a member of the Pacific salmon family, and has been stocked on six continents. It can be found in freshwater streams, rivers and lakes; also in brackish bays and open ocean as steelhead (the sea-run form of the fish, which return to freshwater to spawn).
Rainbow trout prefer cold, oxygenated creeks and streams with plenty of cover and typical riffle, run, pool elements. They also do well in food-rich backcountry lakes.
Rainbow size relates to available forage base and is aided by consistent water temperatures that extend the duration of the growing season. Generally speaking, a two- to three-year-old rainbow trout in a river or lake grows to about 12 inches long, but older fish can easily exceed 20+ inches with the right conditions.