Diagnostic characters: Small to medium-sized fishes with elongate, compressed body that tapers
posteriorly. Body without scales or bony plates. Lateral line complete, running along middle of body
and extending nearly to caudal-fin base. A dendritic organ, located along ventral midline of body just
anterior to anal-fin origin and posterior to anus, found in all marine, and some fresh-water species.
Head broad, slightly depressed. Dorsal profile of head from snout tip to dorsal-fin origin straight or arched.