Trout Identification

Trout and char are the species anglers misidentify most, and slot limits often differ between them. Upload a photo, or use the marks below.

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What trout & char covers

Two different things get called trout. True trout — rainbow, brown, cutthroat — carry dark spots on a lighter body. Char — brook, lake, bull, Dolly Varden — invert that, carrying light spots on a darker body. That one rule resolves more trout identifications than any other, and it matters because many states apply separate limits to brook trout and lake trout despite both being char.

How to identify trout & char

Work through these in order. Each step narrows the shortlist, so the later ones are only needed when the earlier ones leave more than one candidate.

Read the spots before anything else. Dark spots on a pale background means true trout. Pale spots — cream, pink, or blue-haloed — on a dark background means char. Get this right and you have halved the list before looking at a single fin.
For char, check the tail and the fin edges. Brook trout show worm-like vermiculation across the back and dorsal fin, with white leading edges on the lower fins and a square tail. Lake trout have a deeply forked tail and no vermiculation.
For true trout, look under the jaw. A red or orange slash under the lower jaw means cutthroat. A broad pink or red stripe along the flank with heavy small spotting means rainbow. Neither mark on a spotted fish points to brown trout.
Check whether the tail is spotted. Rainbow trout carry spots across the whole tail in radiating rows. Brown trout have few or no spots on the tail and often carry red or orange spots with pale halos on the flank.

Commonly confused species

These are the pairs anglers mix up most often, and each one turns on a single reliable mark.

Brook Trout vs Brown Trout

Brook trout are char: light worm-like vermiculations over a dark back, and white leading edges on the lower fins. Brown trout reverse the contrast: dark spots on a light body, often with pale-haloed red spots.

Rainbow Trout vs Cutthroat Trout

Cutthroat have a red or orange slash under each side of the lower jaw. Rainbows lack the slash and show a pink to magenta band along the flank.

Lake Trout vs Brook Trout

Lake trout have a deeply forked tail and pale spots scattered over the body without vermiculation. Brook trout have a square tail and clear worm-track markings on the back.

Brown Trout vs Atlantic Salmon

Atlantic salmon have a slimmer wrist at the tail, a deeply forked tail, and spots mostly above the lateral line. Brown trout are thicker-tailed with spots scattered well below it.

Where identification goes wrong

Knowing where the marks stop working is most of knowing when to trust them.

Cutbow, a rainbow and cutthroat cross, is common wherever the two overlap and carries a faded throat slash with rainbow-style spotting. Photographs frequently cannot resolve it.
Sea-run and lake-dwelling forms of the same species silver up heavily, losing the spotting and colour the identification depends on. A chrome brown trout is a genuinely hard call.
Spawning colouration changes trout dramatically over a few weeks, so a fish identified confidently in July may look like a different species in October.

Frequently asked questions

What is the difference between trout and char?

True trout have dark spots on a lighter body; char have light spots on a darker body. Rainbow, brown and cutthroat are trout. Brook trout, lake trout, bull trout and Dolly Varden are all char despite their names.

How do you tell a brook trout from a brown trout?

Brook trout are char: they show pale, worm-like markings across a dark green back, white leading edges on the lower fins, and a square tail. Brown trout show dark and red spots on a lighter brown body, no vermiculation, and no white fin edges.

Is a steelhead a rainbow trout?

Yes. A steelhead is a rainbow trout that migrated to the ocean or a large lake and returned. It is the same species, but sea-run fish are far more silver and their spotting and pink stripe are much fainter than a resident rainbow's.

Trout & char in the reference (24)

Every species here has a profile with its range, IUCN status, and identification notes.