Fish identification key

Answer whatever you can while the fish is still in your hands — several of these checks are much harder from a photograph taken afterwards.

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?

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The broadest split, and visible the moment the fish clears the water.

2.What are the markings?

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Horizontal versus vertical is the single most useful distinction among the black bass, and it settles largemouth against smallmouth immediately.

3.Any of these features?

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Pick 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?

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Mouth 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?

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Useful but not decisive — most of these species move between water types, so this only reorders rather than eliminating much.

19 matches

Answer any question to begin