A small, moderately chubby catfish with the rear edge of the tail fin squarish or slightly rounded and the adipose fin forming a low, keel-like ridge rather than a free, flaplike lobe. The dark bar at the base of the adipose fin does not extend to near the fin margin. Pectoral spine with small, sawlike teeth well-developed along the front margin. Body and fins profusely mottled with brownish blotches and bars. Upper jaw projects beyond lower jaw. No dark bar across middle of the tail fin; no dark line across the base of the tail fin. The head length goes fewer than 3.5 times into the standard length.
The genus name, Noturus, means “back tail” and refers to the connection between the adipose fin and the tail that characterizes the madtoms. But the name for this species, eleutherus, means “free” and refers to the almost complete separation of the same two fins!