Brook trout are a type of char belonging to the salmon family, Salmonidae. Also called the speckled trout—is a beautifully colored fish with yellow spots over an olive-green back that usually reaches 9 to 10 inches (23 to 25 centimeters) in length. They are often found in clean, cool streams. These fish are extremely opportunistic and eat a variety of insects, often aquatic insects. They will also eat beetles, ants, and small fish when available.