- 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.
- There are 6-11 oval blotches along the lateral line and 56-68 lateral line scales. The 1st dorsal lobe shows a dark bottom half and a dusky top half.
- The mouth is small and subterminal without obvious teeth; the snout is rounded.
- The 1st dorsal lobe has dark pigments on its lower half, and dusky pigments on upper half; there are 12-15 spines.
- There are 6-11 oval blotches along the lateral line and 56-68 lateral line scales.
- There are 20-23 scales around the caudal peduncle.
- The scales between the pelvic fins are enlarged and toothed; the belly lacks scales.
- Alternative side view.
Mouth and snout: Mouth slightly subterminal, horizontal, minute teeth on jaws. No barbels. Body patterning, color, and scales: Back dark olive. Sides tan, olive, or yellowish with 6-11 oval to square blotches or irregular vertical blotches, sometimes fused to form an irregular lateral stripe. Back with worm-like blotches (vermiculations) or saddles; belly cream. Second dorsal and caudal fins lightly barred, other fins lightly pigmented. 56-68 ctenoid lateral scales. Body shape and size: Body fusiform to cylindrical and elongated; round to oval in cross section. Typically 60-85 mm (2.5-3.5 in) TL; maximum about 111 mm (4.5 in).
Tail, dorsal and other fins: Square to slightly forked tail. Dorsal fin with 2 lobes, distinctly separate, the first with 12-15 (usually 13) spines and the second with 13-15 (usually 13) rays. Pelvic fins thoracic. Adipose fin absent. Anal fin with 2 spines and 10-11 rays.
The blackside darter can be distinguished by its small-to-moderate (not extending beyond the anterior of eye) terminal or subterminal mouth without obvious canine teeth, by the presence of one or more enlarged and heavily toothed scales between the pelvic fins, plus usually a row of enlarged toothed scales along the midline in males and a partially naked belly in females. See also similar species information.
Similar to non-breeders, pigment patterns of male may be more intense.
Similar to adults.
Gilt darter X blackside darter, logperch X blackside darter known from Wisconsin.
|Darter, Blackside||Rounded, not elongated|
|Darter, Gilt||Rounded, not elongated|
|Darter, River||Rounded, not elongated|
|Darter, Slenderhead||Pointed, elongated|
|Logperch||Conical protuberance, somewhat elongated|
|Darter, Blackside||6-11 oval blotches along lateral line, stripe-like, blotches or saddles on back|
|Darter, Gilt||5-8 thick squarish vertical bars or blotches extending on to back|
|Darter, River||8-11 blotches, thick and irregular in back, grading to thin vertical ars in front|
|Darter, Slenderhead||10-16 blotches or irregular vertical bars on sides, back|
|Logperch||15-25 narrow vertical bars|
1st Dorsal Fin Pigmentation
|Darter, Blackside||Solid pigment on lower half, grading to dusky on outer third, thin light edge|
|Darter, Gilt||Solid pigment, orangish in life, except for thin clear/white edge|
|Darter, River||Dusky, with small dark blotch in front, larger dark blotch on posterior membranes|
|Darter, Slenderhead||Dark pigment on lower 1/2, then orange (in life), then dark band, then light edge|
|Logperch||Dusky lateral bands on light background|
Lateral Line Scales
|Darter, Blackside||~10 long gill rakers, 20-23 CP scales, 12-15 D1 spines|
|Darter, Gilt||~11 long gill rakers, 24-29 CP scales, 11-12 D1 spines|
|Darter, River||~9 short gill rakers, 19-24 CP scales, 10-12 D1 spines|
|Darter, Slenderhead||~10 short gill rakers, 23-25 CP scales, 12-13 D1 spines|
|Logperch||~12 short gill rakers, 24-37 CP scales, 13-15 D1 spines|
|Darter, Gilt||Very similar|
|Darter, River||Very similar|
|Darter, Slenderhead||Very similar|
|Darter, Blackside||CP=caudal peduncle, D1=1st dorsal fin|
|Darter, Gilt||CP=caudal peduncle, D1=1st dorsal fin|
|Darter, River||CP=caudal peduncle, D1=1st dorsal fin|
|Darter, Slenderhead||CP=caudal peduncle, D1=1st dorsal fin|
|Logperch||CP=caudal peduncle, D1=1st dorsal fin|