Exhibiting a wide range of colors, they may be olive to blue-gray on the back to white on the belly. Red spots, usually with bluish halos around them, are present on the sides. Characteristic light wavy marks on the back are a distinguishing feature. An obvious white and then black stripe along the fore edge of each of the lower fins aids in separating brook trout from most other trout.
Caudal fin is square or lightly forked.
It is a very hardy trout that competes well with other fishes and endures marginal water qualities better than most trout. It generally has golden- brown hues with yellow under parts. The males during spawning are often brilliantly splashed with crimson spots circled with blue halos. Its upper body is usually profusely dappled with large, irregular dark-chocolate spots. It is quite carnivorous and sports a stronger, sharper set of teeth than most trout.