Brook trout are not trout. Salvelinus fontinalis is a char, the same genus as lake trout and bull trout, and the easy way to tell is the spotting: char carry light spots on a dark body, trout carry dark spots on a light body. A brookie's back is olive with pale, worm-like vermiculations, its flanks carry red spots inside blue halos, and its lower fins are edged in a clean white line ahead of black. It is the most beautiful fish on this site and, in the West, almost always the smallest.
Native in the East, introduced in the West
Brook trout are native to eastern North America: the Appalachians south to Georgia, the Northeast, the Great Lakes basin, and eastern Canada up through Labrador and Hudson Bay. GBIF records for the species are, accordingly, dominated by Pennsylvania, New Jersey, New York and Michigan. Every brook trout west of the Great Plains was introduced, most of them in the late 1800s and early 1900s, and they took hold in exactly the water native cutthroat depended on: small, cold, high-elevation streams and alpine lakes. In the West, GBIF records place brook trout in Wyoming, Colorado, California, Oregon, Idaho, Utah, Montana, Washington, New Mexico, Nevada and Arizona.
That history is why the fish is treated differently depending on where you are. In its native range it is a conservation priority. In much of the Rockies, agencies treat it as an invasive that outcompetes cutthroat in headwaters, and in some drainages they actively remove it or encourage harvest. Yellowstone National Park and several state agencies have brook trout removal programs on specific streams to make room for native cutthroat. Before you decide to release every brookie you catch, check what the agency for that water asks of you.
Why they live where they live
Brook trout need colder water than any other fish on this site except bull trout, and they need it clean. They are also a fall spawner that does well in tiny water, spawning over gravel in streams a rod-length wide and even in spring seeps in lakes. Put those together and you get the Western brook trout habitat: headwater creeks, beaver ponds, alpine lakes above tree line, and the top few miles of a river before it grows into something a rainbow or brown would take over. They rarely grow large in these places because the water is cold and the growing season is short, but they compensate with density and a willingness to eat that no other salmonid matches.
The rivers on this site that list brook trout
Four river pages here record brook trout, and all four describe the same kind of water: small, high and cold.
- Provo River, Upper section, Utah: brook trout are the dominant fish in the headwaters along the Mirror Lake Highway, averaging seven to eleven inches, wild and established, and described as eager attractor dry-fly feeders and an ideal river for learning to read water.
- Uinta River, Utah: brookies in the headwater tributaries, widespread across Uinta Mountain streams, smaller than the native Bonneville cutthroat but aggressive.
- Gibbon River, Wyoming: abundant above Gibbon Falls in Yellowstone, eight to twelve inches, the dominant upper-river species alongside the park's rare grayling.
- Firehole River, Wyoming: present in some of the cold tributaries feeding the thermal main stem, smaller than the river's browns and rainbows but willing on a dry.
Beyond the rivers, Fish Lake in Utah holds splake, the brook trout and lake trout hybrid, which grow far larger than any stream brookie and are taken on big Woolly Buggers along the weed edges at dawn. The Utah, Wyoming and Colorado hubs list every water in those states with recorded brook trout.
How to fish small water for brookies
Brook trout fishing is a stealth and presentation game, not a fly-selection game. The fish are not selective; the water is small enough that they see you. A few habits make the difference.
Use a short rod. A seven-and-a-half- to eight-foot 3-weight handles the overhanging willows and lets you flick short casts into pockets. Keep the leader short too, seven to nine feet, and stay with 4x or 5x because you will be pulling fish out of wood.
Fish upstream and stay low. Brookies hold facing the current in the pools and pockets, and they spook at movement above them. Approach from below, cast to the head of each pocket, and cover a pool in three or four drifts before moving up. A pocket that produces nothing in four casts is usually empty or spooked; the next one is thirty feet away.
Fish dries. From the week runoff clears in the Uintas and Yellowstone, often mid-June, through September, a Royal Wulff, Elk Hair Caddis, Humpy or Parachute Adams in 12 to 16 will catch brook trout all day. A small Stimulator in 12 to 14 works when grasshoppers are on the banks in August. If the fish are down, a size 14 to 16 bead-head Pheasant Tail or Hare's Ear dropped a foot below the dry is the whole nymph box you need.
Fish the color. In September and October, when brookies are staging to spawn, the males turn the deepest orange of any fish in the West and the white fin edges glow. That is also when they are most vulnerable in tiny water, so handle them wet and quick, or photograph them in the net. In alpine lakes, the fall shallow-water window is the one time large brookies come within reach of a fly from shore.
A short list for the first trip
A 3-weight, a spool of 5x, a dozen attractor dries in 12 to 16, six bead-head nymphs, and a map of the Mirror Lake Highway or the Gibbon above the falls. Check the state or park agency for the water, since brook trout limits are often more generous than for other species and, in some places, the agency would rather you kept them. Then walk upstream until the road noise stops and start casting to the next pocket.