Opisthotropis maxwelli
Diet
Mainly aquatic segmented worms; also freshwater shrimp, fishes, frogs and tadpoles
Habitat
Aquatic and nocturnal; 425–1,000 m
Range
Fujian, Guangxi, Jiangxi and Guangdong, China (endemic)
Size
Up to 44 cm
Maxwell's mountain keelback (Opisthotropis maxwelli) is a natricine snake endemic to China, found in south-western Fujian, southern Jiangxi and south-eastern Guangdong, and possibly Guangxi, at 425–1,000 m. It is aquatic and nocturnal. (The Reptile Database; Wikipedia, general species account)
It may reach 44 cm in total length, with a rather long tail making up 20–23% of that. The dorsal scales are keeled in 17 rows, the back is dark olive and the belly yellow. It feeds mostly on aquatic segmented worms, and also on freshwater shrimp, fishes, frogs and tadpoles. (Wikipedia, general species account)