Slender Madtom

Noturus exilis


Image of a slender madtom
Joseph R. Tomelleri. Used with permission.

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


Like all Missouri catfish, this species has smooth, scaleless skin and barbels (“whiskers”) around the mouth. In this species, the adipose fin forms a low, keellike ridge connected to the tail fin, rather than a flaplike lobe. All madtoms have sharp, sawtoothed pectoral spines that have a mild venom. Being stung or pricked by one of the spines cause a burning pain similar to a bee or wasp sting.


Total length: 3-5 inches.

Habitat and conservation

Prefer small- to medium-sized streams with rock or gravel bottoms, clear water and permanent flow. Adults hide beneath rocks during the day and forage actively at night.


Larvae of caddisflies, midges and other aquatic insects, and filamentous algae on the stream bottom.

image of Slender Madtom distribution map
Distribution in Missouri

Common over most of the Ozarks and in the clearer prairie streams of northeastern Missouri.


One of the most common and widely distributed madtoms in our state. It is much too small to be a game fish.

Life cycle

Life span is usually 3 years, but can be up to 6 years in captivity. Spawning is in spring. One parent, probably the male, excavates a nest site beneath a rock and guards the nest and fry until the fry's yolk sacs are absorbed.

Human connections

This catfish adapts well to aquarium life and makes an attractive and interesting aquarium fish. Nongame fishes may be collected for aquarium purposes by the holder of a fishing permit, using techniques and in numbers specified for bait collecting in the Wildlife Code of Missouri.

Ecosystem connections

We all know the story about the "big fish" eating the "little fish." Madtoms are rather small, compared to other catfishes, and as such are more vulnerable to predation throughout their lives. The mildly venomous spines of the madtoms are one adaptation that helps them avoid being eaten.