Head moderately large, broad and horizontal dorsally. Snout short. Eye large, on side of head. Mouth protractile, oblique; posterior of jaw distant from anterior margin of eye. Body elongated, slightly cylindrical and posterior laterally compressed; dorsal profile horizontal, ventral profile arched to end of anal fin. Scales large; longitudinal scales：29-32; predorsal scales：16-17. Dorsal soft rays：7-9; pectoral soft rays：12; pelvic soft rays：6; anal soft rays：8-10 (female). Dorsal fin far behind snout, postdorsal length about two times the length of dorsal fin base; pectoral fins reach pelvic fins; dorsal fin origin slightly behind pelvic fin origin; pelvic fin origin close to middle between snout tip and caudal peduncle end; anal fin rounded. Brownish or grayish, slightly transparent; darker dorsally and grayish white ventrally.
Prefers standing to slow running water, can be found in ponds, paddy fields and slow moving reaches of river, especially vegetated environments. Highly tolerant to low dissolved oxygen and pollution in water. The third, forth and fifth anal fin rays of ma
Northern and Central America. Introduced to Taiwan in 1913, can be found in whole island of Taiwan.