Brown Trout
A close relative of the Atlantic salmon, brown trout were brought to North American waters from Europe. Brown trout have thrived in America, having been introduced into 45 of the 50 states.  They are one of the more popular trout species, possibly due their reputation as a more difficult fish to catch, and in part due to their higher tolerance for warmer waters than other trout species.
 
Brown trout are frequently dark to golden brown along the back, sometimes with brassy appearance. Their yellowish sides are marked with dark brown to black spots, mixed with orange to red spots often haloed in pale blue. The belly is typically whitish. Breeding males often develop a hooked jaw. 
 
Brown trout spawn are fall spawners, starting in late October, sometimes extending into December. Redds are typically dug by the females in gravelly riffles. After the eggs are fertilized the female covers them with fine gravel, then fry hatch the following spring. The diet of adult brown trout includes insects and their larvae, crustaceans, mollusks, amphibians, small rodents and other fish.  Brown trout often actively feed during the day, as long as they are undisturbed. Larger fish typically become more active at night. 

The brown trout was first brought into this state in the 1890s land is now abundant from high mountain streams to broad rivers flowing onto the plains. These fish can be difficult to catch, but many anglers have good success during their fall spawning runs. A large dark spotting pattern and reddish dots can help anglers distinguish these fish from rainbows and cutthroats.

Above courtesy of Colorado Division of Wildlife

Colorado Records

Kept             36.4 inches, 30 lb 8 oz
Released     38 inches

Qualifying length for a Colorado Master Angler Award for Brown Trout is 22 inches.