Brook Trout

Salvelinus fontinalis

A colorful introduced char of Idaho’s cold streams, small rivers, lakes, and reservoirs.

Overview

Size range

10–34 in

Size range

Typical adult length in the waters we cover.

Water temperature

Coldwater

Water temperature

Preferred thermal regime for this species.

Active season

Spring through fall

Active season

When anglers most often encounter this species.

Origin

Introduced

Origin

Stocking and native history where this species is found.

Habitat

Headwater Streams, Rivers & Large Rivers, Lakes & Reservoirs

Habitat

Primary water types where this species is found.

About Brook Trout

Brook trout are introduced to Idaho but are well established in many cold, well-oxygenated waters across the state. They are a favorite of anglers for their bright fall colors, readiness to bite, and presence in smaller streams as well as select rivers and lakes.

Brook Trout Silhouette

Primary

Behavior

spawning: Brook trout spawn in fall, when fish develop vivid colors and move onto clean gravel in cold tributaries, spring-fed areas, or shallow stream margins.
feeding style: Brook trout are coldwater feeders that commonly take drifting subsurface invertebrates, especially as juveniles, and larger fish may also eat small fish.
seasonal notes: They are most at home in cold, well-oxygenated water and often feed best during cooler parts of the day or season. In Idaho streams, they are commonly encountered in headwaters, smaller tributaries, and cooler river sections.

Habitat

water types: small streams, rivers, lakes, reservoirs, headwaters
preferred holds: Look for them in cold, well-oxygenated water near undercut banks, beaver ponds, woody cover, pools, spring influence, and current seams where food drifts past.

Where Found

Blue Ribbon waters

Recommended waters

Diet

They feed mainly on aquatic insects and other drifting invertebrates, with bigger fish sometimes taking small fish.

Angler Tactics

tactics: Fish light tackle and cover water quietly. In streams, target pocket water, plunge pools, undercut banks, and beaver-pond edges; in lakes and reservoirs, work shorelines, inlet areas, and other cool-water margins with small offerings.
effective methods: dry flies, nymphs, small spinners, small spoons, worms

Regulations

Brook trout are not a protected species, but seasons, tackle rules, and bag limits vary by water. Check the specific Idaho Fish and Game rules for your river, stream, lake, or reservoir before fishing; for example, some Bear River reaches list brook trout separately from the general trout limit.

Regulations vary by water. Check current Idaho Fish and Game rules before fishing.