Largemouth bass typically grow larger; trophy smallmouth are heavy for their length but usually run smaller overall.

Do they live in the same lakes?

Often in the same reservoir, but largemouth hold in vegetation and wood while smallmouth favor rocky points and current.

Smallmouth are famous for acrobatic, sustained runs relative to size; largemouth fight deeper with head shakes.

Home / ID guides / Largemouth Bass vs. smallmouth bass

Largemouth Bass vs. smallmouth bass: how to tell them apart

The classic bass confusion. Jaw length, dorsal-fin gap and color pattern separate them in seconds once you know where to look.

Fast comparison

Feature	Largemouth Bass	Smallmouth Bass
Mouth / jaw	Upper jaw extends well past the rear of the eye	Upper jaw stops at or before the rear of the eye
Dorsal fin	Deep notch between spined and soft sections	Shallow notch; the two sections nearly merge
Color pattern	Green sides with a dark lateral blotch chain	Brown-bronze sides with dark vertical bars
Preferred water	Warm, weedy lakes, ponds and slow river banks	Cooler, clearer water with rock, gravel and current

Photograph these features

Straight side view with the mouth closed to show jaw length
Dorsal fin spread so the notch depth is visible
Full flank to capture bars versus lateral blotch
Habitat shot — weeds or rock support the call

When it is not clear-cut

Hybrids of the two occur in some waters and share traits of both. Where the jaw and dorsal clues conflict, treat the call as uncertain and rely on the location and habitat.

Identification tools can be wrong. Confirm uncertain fish with the local fisheries authority before relying on the result for harvest or possession rules.

Compare your catch

Use an AI-assisted suggestion as a starting point, then check the features above yourself.

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Largemouth Bass species guide

Full profile: habitat, baits, seasons and range.

Smallmouth Bass species guide

Full profile: habitat, baits, seasons and range.

Frequently asked questions

Which grows larger?: Largemouth bass typically grow larger; trophy smallmouth are heavy for their length but usually run smaller overall.
Do they live in the same lakes?: Often in the same reservoir, but largemouth hold in vegetation and wood while smallmouth favor rocky points and current.
Which fights harder?: Smallmouth are famous for acrobatic, sustained runs relative to size; largemouth fight deeper with head shakes.

Authoritative references

Micropterus salmoides — Wikipedia
Micropterus dolomieu — Wikipedia