The white catfish is distinguished from all other catfish by its moderately forked caudal fin and short, large head, the width of which is usually greater than the anal fin length. The lower jaw is substantially shorter than the upper jaw. The anal fin is rounded and contains 22 to 24 rays. White catfish always have a gap or depression in the "body ridge" running from the head to the dorsal fin origin. The back is generally dark to medium olive or gray, grading to white on the venter. Fins are light gray, often with a darker membrane between rays. Adult size: 12 to 18 inches.