SCIENTIFIC NAME: Noturus exilis
CHARACTERISTICS: The slender madtom can be separated from other Noturus species in the Tennessee River drainage by the marginal black bands in its median fins and a yellow spot on its nape. Other characters include a strongly depressed head, jaws of equal size, and 17 to 22 anal fin rays. The back is yellowish to medium brown, grading to light yellow below. The caudal fin is short, usually rounded, and mostly black on small individuals. The proximal area becomes lighter with age. Slender madtoms resemble the stonecat, Noturus flavus, but the two can be separated by teeth on pectoral spines and vertical fin color. Stonecats lack well-developed teeth on the rear edge of the pectoral spines (slender madtoms have teeth), and their vertical fins lack a dark margin.
ADULT SIZE: 4 to 6 in (102 to 152 mm)
DISTRIBUTION: Alabama records are limited to the western half of the Tennessee River drainage. Boschung (1992) records a collection from Richland Creek, just across the Alabama-Tennessee line. We collected slender madtoms 13 times at 11 stations in Alabama from 1991 through 1993. Six stations were in Lauderdale County, one each in Lawrence and Marion counties, and three in Limestone County. Future sampling will likely expand the species’ known range.
HABITAT AND BIOLOGY: Slender madtoms usually inhabit riffles in small or medium-sized streams having moderate to swift currents flowing over sand and gravel substrates. Mayden and Burr (1981) record that spawning occurs from mid-June through July in Illinois. Nests are excavated under rocks in pool areas and are guarded by males; females spawn more than once a year. Individuals probably live for five years. Diet consists primarily of immature aquatic insects and small crustaceans. This and most other madtom species feed at dusk and dawn.
ORIGINAL DESCRIPTION: Nelson described the slender madtom in 1876.
Noturus means back tail, referring to fusion of the adipose and caudal fins.
Exilis means slender.
The copyrighted information above is from Fishes of Alabama and the Mobile Basin.