Smallmouth Bass
  • Side view adult.
  • Side view adult.
  • Side view adult.
  • Top view adult.
  • Bottom view adult.
  • Head-on view adult.
  • Close-up flank.
  • Close-up head.
  • Close-up mouth and snout.
  • Close-up tail.
  • Close-up dorsal fin.
  • Close-up anal fin.
  • Close-up pectoral fin.
  • Close-up pelvic fin.
  • The body is fusiform and shows a solid color or slight faint mottling. There are 69-80 lateral line scales.
  • The body is fusiform with faint vertical bars and 69-80 lateral line scales.
  • Close-up dorsal fin: The dorsal fin consists of two dorsal lobes which are moderately connected; the shortest spine is more than half the length of the longest spine.
  • Close-up mouth: The back of the mouth extends to the middle or back of the eye but not beyond. Also notice that the eye is red.
  • Close-up mouth: The back of the mouth extends to the middle or back of the eye but not beyond.
  • Side view of a young-of-year: The tail has a dark caudal spot, the fin is yellow with a dark margin and light tips.
  • Side view of a young-of-year: The tail has a dark caudal spot, the fin is yellow with a dark margin and light tips.
  • Side view of two young-of-year: The tail has a dark caudal spot, the fin is yellow with a dark margin and light tips.
  • Side view of a yearling: Yearlings are similar to adults.
  • Alternative side view.
  • Alternative side view.
  • Alternative view of head.
  • Alternative view of the flank.
  • Alternative view of the caudal region.
DescriptionSimilar Species
Family
Sunfishes (Centrarchidae)
Body
Mouth and snout: Mouth terminal and slightly oblique, with pads of small teeth on the jaws. No barbels. Body patterning, color, and scales: Back dark olive or brown, sides olive or brown, belly cream or white. Sides either a solid color, with dark mottling, or with 9-16 diffuse vertical bars. Fins dusky to darkly pigmented without distinctive markings (but see Juveniles). 69-80 ctenoid lateral scales. Body shape and size: Body fusiform, somewhat laterally compressed and moderately deep; oval in cross section. Typically 300-450 mm (12-18 in) TL; maximum in Wisconsin about 575 mm (23 in).
Fins
Tail, dorsal and other fins: Slightly forked or round tail. Dorsal fin with 2 lobes, broadly joined by a membrane, the first usually with 10 spines and the second with 13-15 rays. Pelvic fins thoracic. Adipose fin absent. Anal fin with 3 spines and 10-11 rays.
Distinguishing Characteristics
See similar species information.
Breeding Adults
Similar to non-breeders; may be darker and more conspicuously marked.
Juveniles
More pronounced bars on sides. Tail fin distinctly marked with a dark spot at base, a yellow-orange cast over most of the tail, and a dark band at the margin (photos).
Hybrids
None known from Wisconsin.
Compare Similar Species
Mouth
Bass, LargemouthExtends to or beyond back of eye
Bass, SmallmouthExtends to middle or back of eye but not beyond
Pigment Pattern
Bass, LargemouthThick, diffuse, irregular (zig-zag) lateral stripe; faint in large adults, pronounced in juveniles; tail of young of year not distincly pigmented
Bass, SmallmouthSolid color, dark mottling, or 9-16 diffuse vertical bars in adults; distinct vertical bars with tail yellow-orange with dark margin in young of year
Lateral Line Scales
Bass, Largemouth60-68
Bass, Smallmouth69-80
Dorsal Fin Lobes
Bass, LargemouthSlightly connected, shortest spine less than half the length of the longest
Bass, SmallmouthModerately connected, shortest spine more than half the length of the longest
Similarity Index
Bass, LargemouthModerately similar
Bass, SmallmouthN/A
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