Mountain Madtom

Noturus eleutherus


Color illustration of Mountain Madtom
Joseph R. Tomelleri. Used with permission.
Species of Conservation Concern

Ictaluridae (bullhead catfishes) in the order Siluriformes (catfishes)


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!


Length: adults from 2 to 3½ inches; maximum about 4 inches.

Habitat and conservation

In Missouri it is known only from large, moderately clear rivers in or near the transition between Ozark and Lowland regions, in gravelly riffles, sometimes where there are thick growths of aquatic vegetation.


Mountain madtoms feed intensely, in relatively short bursts, only at night, and mostly during the first four hours after sunset. They forage among rocks and rooted vegetation, chiefly in riffle areas, for immature aquatic insects, including mayflies, caddisflies, stoneflies and various types of “true” flies.

image of Mountain Madtom distribution map
Distribution in Missouri

Recorded in our state from only a few locations in the southeastern quarter: the Black River near Poplar Bluff, the St. Francis River near Sam Baker State Park and the Current River near the Arkansas state line.


State Endangered; a Species of Conservation Concern in Missouri. This fish is more common east of the Mississippi River. Habitat degradation resulting from human land use near streams jeopardizes the populations in our state. Siltation, sedimentation and pollutants seeping from nearby lands degrade the aquatic habitat mountain madtoms require.

Life cycle

In our state, mountain madtoms probably spawn in May and June, depositing eggs beneath rocks in shallow, shaded pools having a floor of clean-swept fine gravel. As with most catfish, there is parental care: Males guard the eggs and continue to watch over the larvae for a few days after hatching. Mountain madtoms live for about 4 or 5 years, with males living longer and attaining greater lengths than females.

Human connections

Missourians can be proud of our state for many reasons. One bragging point we have over most of the neighboring states is the richness of our fish community, including rare types like this madtom. There are more than 200 kinds of fish in our state. Kansas, for example, only has about 140.

Ecosystem connections

Like many fish of its size, this madtom plays an intermediate role in the food chain: It preys on smaller creatures but is preyed upon by larger animals. Like other madtoms, this species has a mild venom in its pectoral and dorsal spines that helps protect it from predation.