Tadpole Madtom
  • Side view adult.
  • Side view adult.
  • Side view adult.
  • Bottom view adult.
  • Top view adult.
  • Head-on view adult.
  • Close-up flank.
  • Close-up head.
  • Close-up mouth and snout.
  • Close-up tail (some pieces of the upper tail lobe are missing, but are partially healed).
  • Close-up dorsal fin.
  • Close-up anal fin.
  • Close-up pectoral fin.
  • Close-up pelvic fin.
  • Close-up head: The upper and lower jaws are about equal in length.
  • The sides show a thin dark lateral stripe and no dark edges on dorsal, anal, or tail fins; the body is relatively deep.
  • Close-up pectoral fin: Notice that the pectoral spine is smooth without saw-like teeth.
  • Close-up of caudal region: The adipose fin continuous with caudal fin; there may be a shallow or no notch between them.
  • Close-up inside of mouth: Notice the lack of horn-like backward lateral extensions of the tooth patch on the roof of the mouth.
  • Alternative side view: Notice the partially healed notch out of the top of the tail near the connection with the adipose fin.
  • Alternative side view, pieces of the upper caudal lobe are missing.
DescriptionSimilar Species
Bullhead Catfishes (Ictaluridae)
Mouth and snout: Terminal or slightly subterminal, 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: Solid color often with a faint thin dark lateral stripe. Color dark brown, dark olive, or black, often with a pencil-thin, black, lateral strip; belly tan or yellow-brown. Fins and barbels moderately to darkly pigmented (chin barbels often tan); dorsal, anal, and tail fins without darker margins. No scales. Body shape and size: Body dorsal-ventrally flattened with a rounded head; in cross section approximately oval (with a long horizontal axis) to round with a flattened ventral surface. Typically 45-75 mm (1.5-3 in) TL; maximum in Wisconsin about 117 mm (4.5 in).
Tail, dorsal and other fins: Rounded tail. Single dorsal with 1 stout spine and usually 6 rays, attached by membrane. Pelvic fins abdominal. Adipose fin present, attached to caudal by a membrane with no or a very shallow notch between them. Anal fin with 14-16 rays (including rudimentary rays).
Distinguishing Characteristics
The tadpole madtom can be distinguished by its adipose fin, which is attached to the back and caudal fin. See also similar species.
Breeding Adults
Similar to non-breeders.
Similar to adults.
Compare Similar Species
Tooth Patch on Roof of Mouth
Madtom, SlenderNo horn-like backward lateral extensions
Madtom, TadpoleNo horn-like backward lateral extensions
StonecatHorn-like backward lateral extensions present
Color Pattern
Madtom, SlenderNo dark lateral stripe; dorsal, anal, tail fins usually with darker edges
Madtom, TadpoleOften with pencil-thin dark lateral stripe; dorsal, anal, tail fins without darker edges
StonecatNo dark lateral stripe; dorsal, anal, tail fins with lighter edges or sometimes uniformly pigmented
Pectoral Spine
Madtom, SlenderProminent saw-like teeth on posterior margin
Madtom, TadpoleNo or a few very fine teeth
StonecatNo or a few very fine teeth
Jaw Lengths
Madtom, SlenderAbout equal or upper very slightly longer
Madtom, TadpoleAbout equal or upper very slightly longer
StonecatUpper clearly longer than lower (i.e., subterminal mouth)
Body Depth/Std Length
Madtom, Slender<22%
Madtom, Tadpole>22%
Similarity Index
Madtom, SlenderVery similar
Madtom, TadpoleN/A
StonecatVery similar