Rainbow Trout (Oncorhynchus mykiss) — identification, habitat & look-alikes

Rainbow Trout is a cold-water fish native to western North America and widely stocked elsewhere in the United States. Some Rainbow Trout stay in fresh water, while others grow at sea and return to fresh water to spawn; the sea-going form is called .

Appearance

Appearance: Dark spots cover the back and often the tail, and many fish have a pink stripe along the side. Sea-run fish can look much more silver.

Look-alikes

Cutthroat TroutOncorhynchus clarkii

Look for red or orange slashes under the lower jaw on a cutthroat trout. Some fish lack obvious slashes, and hybrids can blur the difference.

Why they get mixed upBoth are spotted western trout that can share streams.

Brown TroutSalmo trutta

Brown Trout usually has red or dark spots with pale rings; Rainbow Trout usually has many small dark spots and may have a pink side stripe.

Why they get mixed upBoth are common in stocked U.S. trout waters.

Where it lives

Typical habitats: Cool streams
Lakes
Pacific coastal waters
Range: It is native to Pacific drainages from Alaska to southern California. Stocking has spread it to many other U.S. states.
Preferred conditions: Spawning fish need cool streams with clean gravel.
Migration: Steelhead grow at sea and return to fresh water to spawn; resident rainbow trout stay in fresh water.
When it’s recorded: Recorded year-round, every year · most records in Jun–Jul
10,050 observations in the US · 10 years · for referenceChoose a state

Behavior

Diet: It eats aquatic and land insects, crustaceans, fish eggs, and small fish.

Life cycle

Breeding season: In Oregon, rainbow trout and steelhead generally spawn in spring.
Nest: Females dig nests in stream gravel. Some fish survive to spawn again.

Name and classification

Varieties and forms: Regional forms include Coastal Rainbow Trout and redband trout.

Conservation

IUCN Red List: LCLeast ConcernLow risk of extinction

Culture and stories

Culture and stories: Rainbow Trout is a popular sport fish.

9 sources