How to identify a Black Bullhead
The black bullhead may be dark green, olive, brown, yellowish-green, or black on top, green or gold on the sides, and white or bright yellow below. Spawning males are jet black, as are the very young (the young of brown and yellow bullheads are also usually black). The surest way to distinguish this fish from the brown or yellow bullheads is by the pectoral fins. In the brown and yellow bullheads the rear edge of the pectoral fin spine is serrated with numerous sharp tooth-like projections, while the black bullhead the serrations are extremely weak or absent altogether. Also, the black bullhead has dark-colored chin barbels which may be gray, black, or black-spotted, and its body and head are deeper and more massive than in the brown or yellow bullheads. The tail fin is squarish (truncate) or slightly emarginate, which will readily distinguish the black bullhead from the channel catfish (Ictalurus punctatus), the white catfish (Ameiurus catus), and the blue catfish (Ictalurus furcatus), all of which have deeply forked tails.