Smallmouth vs Largemouth Bass: How to Tell Them Apart

Smallmouth bass painted by Duane Raver for the U.S. Fish and Wildlife Service: bronze flank with vertical bars and a jaw that stops under the eye — Illustration: Duane Raver, U.S. Fish and Wildlife Service (public domain)

Close the fish’s mouth and look where the upper jaw ends. On a largemouth bass it reaches past the rear edge of the eye; on a smallmouth bass it never does. That single mark settles smallmouth vs largemouth on nearly every fish you will ever hold. The flank backs it up: a largemouth wears a dark horizontal stripe on green, a smallmouth vertical bars on bronze.

A largemouth’s upper jaw reaches past the eye; a smallmouth’s stops under it. Learn that one mark and you will never mix them up again.

How do you tell them apart?

The jaw comes first, the stripe second. The rest of the table confirms what those two have already told you.

Feature	Largemouth bass	Smallmouth bass
Upper jaw	Extends well past the rear edge of the eye	Never extends beyond the eye
Flank pattern	Dark blotches joined into a horizontal stripe	Dark vertical bands, no horizontal stripe
Color	Green back, pale belly	Bronze to brown, hence “bronzeback” and “brown bass”
Dorsal fin	Nearly divided in two; 9 spines, 12–13 soft rays	Shallow notch, one continuous fin; 13–15 soft rays
Eye	Usually dark	Often red or orange-tinted
Scientific name	Micropterus nigricans (until 2022 M. salmoides)	Micropterus dolomieu
All-tackle record	22 lb 4 oz (10.1 kg), Georgia, 1932; tied in Japan, 2009	11 lb 15 oz (5.4 kg), Dale Hollow Lake, 1955
Common length	16 in (41 cm), USFWS	12–16 in (30–41 cm) in most waters

Two more checks help when the fish is small or the light is bad. The dorsal fin on a largemouth is so deeply notched that the spiny front half and the soft rear half look like two separate fins. On a smallmouth the notch is shallow and the fin reads as one. And smallmouth often carry three dark bars radiating back from the eye across the cheek, which largemouth lack.

Color alone can fool you. A largemouth from stained water can be nearly black, and a smallmouth from a clear lake can look pale olive. The jaw and the stripe do not change with the water.

Largemouth bass painted by Duane Raver: the upper jaw reaching past the eye, the horizontal stripe and the deeply notched dorsal fin

The largemouth, for comparison: the jaw runs past the eye and the flank carries a horizontal stripe. Illustration: Duane Raver, U.S. Fish and Wildlife Service (public domain).

Where does each one live?

The two species split the country’s water between them by temperature, clarity and bottom.

Largemouth are native east of the Rockies, from the Great Lakes down the Mississippi basin to northern Mexico, and have been stocked almost everywhere else. The U.S. Fish and Wildlife Service describes their home as “clear, vegetated lakes, ponds, swamps, and the backwaters of pools, creeks and rivers.” They want cover: weed beds, laydowns, docks, flooded brush. Texas Parks and Wildlife adds that they “prefer clear quiet water, but will survive quite well in a variety of habitats.” That is why a farm pond and a muddy reservoir both hold them.

Smallmouth are native from Minnesota and southern Quebec south to the Tennessee River and west to eastern Oklahoma. They now live in most states except Florida and Louisiana. Their water is cooler and cleaner: lakes larger than 100 acres and deeper than 30 ft (9 m) by the Texas profile, and cool, clear, gravel-bottomed streams. In one line, they want a rocky stream or lake where crayfish are abundant. In Wisconsin’s survey, a good smallmouth stream has a summer water temperature above 72 °F (22 °C), coarse rock and gravel, and pools 3–4 ft (1–1.2 m) deep.

The practical rule at the ramp: weeds and wood, think largemouth; rock, gravel and current, think smallmouth. Many lakes hold both. There the largemouth own the weedy bays while the smallmouth own the rocky points and reefs.

How do their seasons differ?

Both species spawn when the water reaches about 60 °F (16 °C), and in both the male builds and guards the nest. The differences are in the nest site and the timing.

	Largemouth	Smallmouth
Spawn trigger	About 60 °F; USFWS gives 59–75 °F (15–24 °C)	About 60 °F; Wisconsin DNR gives usually 62–64 °F (17–18 °C), recorded as low as 53 °F
Season	February in the South to May in the North	Mostly May and June; mid-May through June in southern Wisconsin
Nest site	Sand, mud or gravel in 2–8 ft (0.6–2.4 m) among vegetation	Gravel bed next to a log or boulder in 3–10 ft (1–3 m); downstream of boulders in streams
Eggs	2,000–43,000	2,000–15,000; average nest about 2,500
Hatch	5–10 days	About 10 days in the mid-50s °F, 2–3 days in the mid-70s
Male guards	Fry for 7–10 days	Up to a month

Because smallmouth spawn a little later and in cooler water, a lake with both species gives you two spawns a few weeks apart. The largemouth are on beds in the back of the bays first. The smallmouth follow on the gravel flats and rocky shorelines as the main lake warms.

Through summer the largemouth stay with cover in the shallows or move to deep weed edges. Smallmouth drop onto rock humps, points and river channel edges and feed on crayfish. In fall both chase baitfish. In winter, smallmouth in particular gather in deep, slow water, where they can be caught in numbers on a jig or a blade bait.

Which grows bigger, and which fights harder?

Largemouth are the bigger fish. The all-tackle record is 22 lb 4 oz (10.1 kg), caught by George Perry at Montgomery Lake, Georgia, in 1932. Manabu Kurita tied it at Lake Biwa, Japan, in 2009. A 10-pounder is a fish of a lifetime in most states. Growth in Texas runs 4–6 in (10–15 cm) in the first year, 8–12 in at two years and 16 in (41 cm) at three.

The smallmouth record is 11 lb 15 oz (5.4 kg), caught by David L. Hayes at Dale Hollow Lake on the Tennessee–Kentucky line on July 9, 1955. The fish was struck from the record book in 1996 after an affidavit alleged weight had been added, and reinstated after later documentation. A 5 lb (2.3 kg) smallmouth is a trophy almost anywhere; a 6 lb fish is news.

On the fight, the smallmouth has the reputation: pound for pound, it pulls harder. It jumps more, runs longer and does not give up at the boat. Largemouth make one or two heavy surges and a head-shaking jump, then come in. Part of that is water. Smallmouth live in cooler, better-oxygenated water and current, and they are built for it.

How do you fish for each one?

The tackle overlaps; the presentations lean different ways.

Largemouth: cover fishing. Texas-rigged plastics and jigs flipped to wood and grass, spinnerbaits and chatterbaits along weed edges, topwater frogs over mats in summer. Medium-heavy casting gear, 15–20 lb fluorocarbon or braid. The how to catch bass page and the best bass lures list go deeper.
Smallmouth: rock and current, usually smaller baits. Tubes and Ned rigs dragged on gravel, drop shots on deep rock, small crankbaits and jerkbaits along points, topwater walkers on calm mornings. Spinning gear, 6–10 lb fluorocarbon, is the standard. Crayfish colors (green pumpkin, brown, orange) match what they eat.

Both species pages, largemouth bass and smallmouth bass, carry the full season tables. The bass hub sets these two beside the spotted, Alabama and Guadalupe bass, which are more often confused with each other than with either of these.

Which bass looks like both?

A spotted bass looks like a largemouth with a smallmouth’s jaw; the types of bass page sorts the rest of the family. It has the horizontal stripe of a largemouth, but the upper jaw stops at the rear edge of the eye. Its dorsal fin is only shallowly notched, and it carries a rough tooth patch on the tongue that neither largemouth nor smallmouth have. Rows of dark spots below the lateral line give it its name. The spotted bass page shows how to separate it from the Alabama bass, which by eye you cannot.

Gear for bass

Gear guide
Best Bass Lures: What Won the 2025 and 2026 Elite Series, Season by Season
Best bass lures from two seasons of Elite Series winning baits: a lure for each water color, depth, cover and season, with smallmouth and spotted bass picks.