Etheostoma erythrozonum is a relatively large, stout-bodied species of Etheostoma. Dorsal-fin spines (11?14, modally 13), dorsal-fin rays (12?14, modally 13), anal-fin rays (8?10, modally 9), principal caudal rays (16?18, modally 17), pectoral-fin rays (15?17, modally 16), lateral-line scales (39?55, modally 50), cheek scales absent, opercle partially scaled (0?9 scales, modally 5), breast partially to completely scaled, nape completely scaled. Both males and females of this species have four prominent dark saddles on the back and dorsal sides, with the sides angled obliquely forward. The background color is dusky in the dorsal region, lighter in the sublateral region and white on the belly. Along the sides is a series of sub-lateral dark blotches. There is a dark preorbital bar extending forward and a dark suborbital bar extending down the cheek. This species exhibits extreme sexual dimorphism in nuptial color patterns.