The yellow bullhead ranges in color from olive to brown to almost black dorsally with a yellow or white belly and yellow or brown sides that are never mottled as they often are in the brown bullhead (A. nebulosus). Juveniles usually have dark brown to jet black bodies. It is the only bullhead in which the chin barbels are yellow, buff or pale pink instead of dark in color. The upper barbels are brown. The tail is rounded which helps to distinguish the yellow bullhead from the brown bullhead and the black bullhead (A. melas), which have truncate or slightly emarginate tails. An even better distinction between yellow and black bullheads is the spine at the top of the pectoral fins. In the yellow bullhead, as in the brown, this spine has sharp, tooth-like serrations along the back edge. In the black bullhead it is either not serrated at all or only very weakly serrated.

The flesh of this small catfish is whiter than that of the brown bullhead, rather cream-colored, and of excellent quality.