Brook trout
Brook trout "(Salvelinus fontinalis") were widely stocked in park waters beginning in 1890. Preferring cooler water, brook trout were easily displaced by introduced brown and rainbow trout in the lower reaches of the major river systems. Today brook trout exist in the upper Firehole River above Kepler Cascades and in other Firehole tributaries like the Little Firehole River, Iron Spring and Sentinel Creeks. In the Gardner River drainage they are common above Osprey Falls. They also occur in many lakes and ponds. Brook Trout are found in the Middle Creek drainage of the Shoshone River and tributaries of Shoshone Lake.