Madtoms are freshwater catfishes (order Siluriformes) of the genus Noturus of the family Ictaluridae.

It is the most species-rich genus of catfish in North America,[1] native to the central and eastern United States, and adjacent parts of Canada.

The more conspicuously variable attributes of these secretive fishes are features of pigmentation, which also are more difficult to quantify and often vary according to substrate and water quality.

[2] These species have small to tiny or fragmented ranges, and aspects of pigmentation are important diagnostic characters of each.

[3] A number of madtom species are narrowly distributed and extremely rare, and thus are at great risk of extinction.