Trout are valued highly both for commercial fisheries and for sport. Trout are an important food source for humans and wildlife including brown bears, birds of prey such as eagles, and other animals. The eggs take two to three months to hatch, and the newly hatched trout, or fry, become known as fingerlings when they leave the nest and begin feeding on plankton. The few forms that migrate to sea between spawnings return to streams at this time. Trout spawn between fall and spring and bury their eggs in a gravel nest scooped out by the female on a streambed. The food items that are most important to trout and fly fishers are the aquatic insects that spend most of their life cycles underwater in rivers, streams, and stillwaters. Trout eat a host of aquatic insects, terrestrial insects, other fish, crustaceans, leeches, worms, and other foods. Lake trout can live many decades, and can grow to more than 30 kilograms (66 lb). Lake trout inhabit many of the larger lakes in North America, and live much longer than rainbow trout, which have an average maximum lifespan of 7 years. Mostly, these colors and patterns form as camouflage, based on the surroundings, and will change as the fish moves to different habitats. Trout that live in different environments can have dramatically different colorations and patterns. Trout usually live in cool water about 10–16 ☌ (50–60 ☏), often among submerged objects or in riffles and deep pools.

Interesting facts about brook trout