Flathead Catfish
  • 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 sides show a mottled color, a round/square tail, a "free" adipose fin, and a flattened head.
  • The anal fin has 14-16 rays, including rudimentaries, with a rounded margin.
  • Close-up head: The upper jaw is shorter than the lower; the head is flattened.
  • Close-up inside of mouth: There are horn-like backward lateral extensions from the tooth patch on the roof of the mouth.
  • The anal-fin base is shorter than post-orbital distance.
  • Side view of a yearling: Juveniles are similar to adults, but show a distinctly light area for the upper tail lobe.
  • Side view of a yearling: Juveniles are similar to adults, but show a distinctly light area for the upper tail lobe.
  • Close-up tail of a yearling: Juveniles are similar to adults, but show a distinctly light area for the upper tail lobe.
DescriptionSimilar Species
Family
Bullhead Catfishes (Ictaluridae)
Body
Mouth and snout: Superior, patches of numerous fine teeth on jaws. 8 obvious barbels (4 pairs; 2 pair on chin, 1 pair on side of upper jaw (near corner of mouth), 1 pair on top of snout). Body patterning, color, and scales: Mottled with irregular blotches (mottling may be faint in turbid water). Color brown, dark yellow, or dark olive, with dark brown or black mottling; belly cream or tan. Fins and barbels moderately to darkly pigmented (chin barbels often much lighter). No scales. Body shape and size: Body dorsal-ventrally flattened with a broad flat head; in cross section oval (with a long horizontal axis). Typically 500-800 mm (20-32 in) TL; maximum in Wisconsin about 1150 mm (46 in).
Fins
Tail, dorsal and other fins: Rounded, square or slightly forked tail. Single dorsal with 1 stout spine and usually 6 rays, attached by membrane. Pelvic fins abdominal. Adipose fin present. Anal fin with 14-16 rays (including rudimentary rays).
Distinguishing Characteristics
The flathead catfish can be distinguished by its “free”, flaplike adipose fin, in having its lower jaw clearly extending past its upper, in having the tooth patch in the roof of its upper jaw with horn-like lateral backward extensions, and in having its anal fin base shorter than its post-orbital distance. See also similar species information.
Breeding Adults
Similar to non-breeders.
Juveniles
Similar to adults, but pelvic and anal fins and most of tail particularly dark with upper lobe of tail tan or cream, in strong contrast to rest of tail.
Hybrids
None reported from Wisconsin.
No similar species.
Compare Similar Species
Comment
Catfish, FlatheadThe flathead catfish is moderately similar to the madtom (Noturus) species, the bullhead (Ameiurus) species, the channel catfish, and the blue catfish. It can be distinguished from madtoms by its “free”, flaplike adipose fin (vs. fused to back and caudal fin). It can be distinguished from the bullheads and channel catfish and blue catfish in having its lower jaw clearly extending past its upper (vs. the upper extending beyond the lower), in having the tooth patch in the roof of its upper jaw with horn-like lateral backward extensions (vs. extensions absent), and having its anal fin base shorter than their post-orbital distance (vs. longer).
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