Brook trout from streams have pale markings on a dark green background. The back is covered with wormlike marks. Lake Superior fish are more silvery with less distinct markings. In both stream and lake fish, the tail is nearly square, and the leading edge of each lower fin often has a white margin. The brook trout rarely exceeds a pound in small streams.
Lakes produce larger fish.
Introduced from Europe to much of the United States during the late 1800's, the brown trout has adapted well, tolerating warmer water than the native brookie and supplanting it in many waters throughout the state. Young brown trout feed on aquatic insects and other invertebrates. As browns exceed a foot in length, they seek chubs, dace and other small fish. Brown trout are warier and harder to catch than brook trout and can live in streams too warm for brookies. Browns also grow faster and larger.