Most readily distinguished from its only congener, T. tonlesapensis, by much larger head, larger eye, larger pharyngeal bone and fewer anal fin rays, scales and vertebrae. Anal fin origin on a vertical with dorsal fin origin (versus anal fin origin far in advance of dorsal fin origin in T. tonlesapensis). Snout tip projects strongly beyond upper jaw, thus differing strikingly from T. tonlesapensis, in which it projects but very slightly. However, in one paratype of T. smaragdinus, the snout tip projects little more than in T. tonlesapensis.