The upper flanks are frequently marked with spots which are occasionally arranged in vertical bars.

The upper gill cover is dark and contrasts with the pale lower part and cheek.

[2] The blenny darter's habitat is gravel and rubble riffles in creeks and small to medium rivers which have clear water.

[3] The blenny darter was first formally described in 1887 by the American zoologists Charles Henry Gilbert (1859–1928) and Joseph Swain (1857–1927) with the type locality given as Cox's Creek and tributary of the Tennessee River near Florence, Alabama.

[8] Herbert T. Boschung and Richard L. Mayden (2004) recommend Etheostoma blennius for Special Concern status in Alabama due to its limited distribution.

Much of the area in Alabama where the species occurs is proposed for a number of floodwater-retarding dams, and such structures would greatly degrade the remaining habitat.