The body is elongate and sub-cylindrical, becoming highly compressed toward the tail and caudal fin, with a marked median keel on the caudal peduncle. The dorsal and ventral profiles of the fish are nearly evenly convex, with the two profiles intersecting at the pointed snout. The anal fin consists of two anteriorally detached spines followed by a single spine attached to 16 or 17 soft rays. In both the dorsal and anal fins, the posterior 7-10 rays are detached and form a series of diagnostic finlets. The curved section of the lateral line has 21 to 29 scales, while the straight section has 51 to 59 very large scutes.