dark olive to brown; head large and fleshy, not flattened; 13-15 rays in anal fin; narrow, dark line along side of body; rarely exceeds 3-4 inches in length
eastern two-thirds of state, in large interior rivers and the Mississippi River
insects, occasionally algae and other aquatic plants
The tadpole madtom is widely distributed in the large interior rivers and the Mississippi River. Populations reach their greatest abundance in the small, rocky, clear-water streams, particularly in the northeastern and northcentral regions. Its presence in many of the oxbow lakes along the Missouri indicates that it is also present in the parent stream. This species is occasionally taken in the natural and man-made lakes of the state.
Color of the tadpole madtom varies from dark olive or brown to sometimes dark gray and light beneath. The head is large and fleshy and not flattened. The body is short and stout. It more closely resembles the bullhead than either of the other madtoms. There are from 13 to 15, usually 14, rays in the anal fin. The premaxillary band is bar shaped. There is a conspicuous, very narrow dark line along the side of the body. Upper and lower jaws are of equal length. This little fish rarely exceeds 3 or 4 inches in length.
Female madtoms usually mate several times during the June through July breeding period. Young specimens have been taken in collections in late fall measuring about one inch long. Most individuals probably mature during their second summer and few live beyond their third summer.
Like most madtoms, this species is most active at night, feeding on insects, and occasionally on algae and other aquatic plants. These catfishes, as well as the other madtoms, are equipped with a poison gland at the base of the pectoral fin. When one is stung or pricked by one of the spines, there is a burning sensation similar to a bee or wasp sting.