Anderson's Stream Snake

Anderson's stream snake or Anderson's mountain keelback (Opisthotropis andersonii) is a colubrid snake recorded from Hong Kong and Vietnam. It prefers forest and freshwater wetlands at 300–900 m, and adults measure 38–46 cm in total length. (The Reptile Database; Wikipedia, general species account)

It is blackish olive above and whitish below except for a brown chin and lower lips. The snout is short, broad and depressed, and the 17 rows of dorsal scales are smooth on the neck, feebly keeled at midbody and strongly keeled on the tail. (Wikipedia, general species account)