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TroutSalmonidaeG4 (Apparently Secure) · ESA: Not listed · Idaho: S4Anadromous

Cutthroat Trout

Oncorhynchus clarkii

Idaho’s native trout, built for cold streams and lakes and famous for rising to a well-drifted fly.

Overview

Size range

8–39 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

Native

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 Cutthroat Trout

Cutthroat trout are native to Idaho and part of the state’s angling heritage. They thrive in cold water, and while some forms are sea-run, many Idaho populations live entirely in freshwater streams and lakes.

Also known as: Cutthroat

Cutthroat Trout Silhouette

Primary

Behavior

spawning: They typically spawn in streams over gravel, with adults moving into tributaries or stream reaches during the spawning period.
feeding style: Opportunistic feeders that take insects readily, but also eat small fish and crustaceans when available.
seasonal notes: Most active in cold, well-oxygenated water; surface feeding can be especially good when aquatic insects or terrestrials are present.

Habitat

water types: cold streams, rivers, mountain lakes
preferred holds: Look for them in clear, cold water around riffle seams, undercut banks, pool tails, and lake inlets or shorelines with food drifting nearby.

Where Found

Blue Ribbon waters

Recommended waters

Diet

They feed on insects, crustaceans, and small fish, with terrestrials often a key warm-season bonus.

Angler Tactics

tactics: Match the food base and keep presentations natural. In streams, cover seams, pocket water, and gravelly runs; in lakes, work shorelines, inlets, and drop-offs during low-light periods.
effective methods: dry flies, nymphs, small streamers, terrestrial patterns, spinners and spoons

Regulations

Idaho seasons, limits, and gear rules vary by water, and cutthroat regulations can differ among rivers and stream sections—always check the specific IDFG rules for your exact water before fishing.

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