Rainbow Trout vs Brown Trout

The check that settles it

Brown trout has red or orange spots with pale halos and few or no spots on the tail.

Why this matters beyond curiosity

  • Look-alike species often carry different limits. Walleye and sauger, black and white crappie, pike and muskie, blue and channel catfish — each pair can have different sizes, seasons and daily limits in the same water.
  • Check it before the fish goes in the livewell. Most of the tests on this site take seconds and are far easier on a fish you are still holding.
  • If you cannot tell, release it. That is the answer that is never wrong, and it is the one a warden will not argue with.
  • Regulations are set by your state or province and change annually. This site identifies fish; it does not tell you the rules. Check the current regulations for the water you are on.

Rainbow Trout

Trout and char

Oncorhynchus mykiss

Markings
spots, horizontal stripe
Body
torpedo
Typical size
0.56 lb
Regulations
Trout waters commonly have separate seasons, stamp requirements, tackle restrictions and daily limits distinct from general fishing regulations.

Brown Trout

Trout and char

Salmo trutta

Markings
spots
Body
torpedo
Typical size
0.58 lb
Regulations
Often subject to specific trout regulations and, in wild-trout streams, to gear restrictions and catch-and-release rules.

Confirming a rainbow trout

  • Black spots covering the entire tail, top to bottom.
  • Pink or red band along the flank, though this fades on silvery lake fish.
  • Spots on a light background, unlike brook trout's light marks on dark.
  • Adipose fin present, as on all trout and salmon.

Confirming a brown trout

  • Red or orange spots with pale halos on the flank.
  • Few or no spots on the tail — the clearest separation from a rainbow.
  • Golden-brown or buttery ground colour.
  • Square-ish tail with little fork.