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What fish is this? Check before it goes in the livewell.
Most identification questions on the water are not really about the species — they are about the limit. Walleye and sauger, black and white crappie, pike and muskie all look alike and are regulated differently, and each pair is separated by one check that takes a couple of seconds with the fish in your hand.
Fish Identifier: ID Scanner — Free★ 4.0 · 4 ratings · iPhone & iPad
- Confusable pairs side by side
- Limits are set by your state — always check
- Nothing you enter leaves your browser
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.
1.What shape is the body?
optionalThe broadest split, and visible the moment the fish clears the water.
2.What are the markings?
optionalHorizontal versus vertical is the single most useful distinction among the black bass, and it settles largemouth against smallmouth immediately.
3.Any of these features?
optionalPick everything you can see. Whiskers mean catfish. A small fleshy fin ahead of the tail means trout, salmon or catfish. Two separate dorsal fins rules out most of the list.
4.Where is the mouth?
optionalMouth position tells you how the fish feeds, and it separates crappie from other panfish and carp from most natives.
5.What water are you fishing?
optionalUseful but not decisive — most of these species move between water types, so this only reorders rather than eliminating much.
- Black CrappiePanfish
- Blue CatfishCatfish
- BluegillPanfish
- Brook TroutTrout and char
- Brown TroutTrout and char
- Channel CatfishCatfish
- Common CarpCarp and suckers
- Flathead CatfishCatfish
- Largemouth BassBlack bass
- MuskellungePike and muskie
- Northern PikePike and muskie
- PumpkinseedPanfish
- Rainbow TroutTrout and char
- SaugerPerch family
- Smallmouth BassBlack bass
- Spotted BassBlack bass
- WalleyePerch family
- White CrappiePanfish
- Yellow PerchPerch family
The pairs that matter
Different limits, nearly identical fish.
All species
The fish most commonly caught across North America.
Largemouth or smallmouth? Drop a line from the back of the eye
Questions people ask
How do you tell a largemouth from a smallmouth bass?
Close the mouth and look at the upper jaw. On a largemouth it extends past the rear edge of the eye; on a smallmouth it stops at or before it. Largemouth also has a ragged horizontal stripe along the side, while smallmouth has vertical bars and a bronze cast.
How do you tell black crappie from white crappie?
Count the stiff spines at the front of the dorsal fin. Seven or eight means black crappie; five or six means white crappie. Black crappie also has irregular scattered mottling, while white crappie has faint vertical bars.
How do you tell a walleye from a sauger?
Walleye has a white tip on the lower lobe of the tail and no spots on the spiny dorsal fin membrane. Sauger has distinct rows of dark spots on that fin and no white tail tip.
Is there an app that identifies fish from a photo?
Yes — Fish Identifier, and this site is its free web companion. Both answer the species question. Neither answers the one that follows it, which is whether you may keep the fish — limits and seasons are set by your state or province and change every year, so check the current regulations before anything goes in the cooler.
Is this site free?
Yes — the key, every species page and every comparison, with no account and no email. Nothing you select leaves your browser. The app is a free download for photo identification and offline use on the water.
Which fish are most often misidentified?
The pairs that share water and look alike at a glance: largemouth and smallmouth bass, black and white crappie, walleye and sauger, channel and blue catfish. These matter more than most misidentifications because the pairs frequently carry different size or bag limits, so getting it wrong is a citation rather than an embarrassment. Each pair has one character that settles it, and it is usually not the one people reach for.