Thryssocypris smaragdinus Roberts & Kottelat 1984

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.

Dorsal soft rays (total): 9 - 10; Analsoft rays: 12 - 14; Vertebrae: 38 - 39

Thryssocypris smaragdinus is a species of cyprinid of the genus Thryssocypris. It inhabits western Borneo in Indonesia. It has not been evaluated on the IUCN Red List, was described in 1984 and is considered harmless to humans. Its maximum length among unsexed males is 5.4 centimetres (2.1 in). It has 9 to 10 dorsal soft rays, 12 to 14 anal soft rays and 38 to 39 vertebrae.