Slender-necked Sea Snake

The slender-necked sea snake (Hydrophis melanocephalus) is a venomous sea snake of the family Elapidae, recorded in the South China Sea off Guangxi and Fujian in China and off Vietnam. (The Reptile Database; Wikipedia, general species account)

The head is black with a yellowish bar on the prefrontals. The front of the body is black with yellow crossbars on the back, while the rear is olive above and yellow below with black rings that are broader on the back. The neck scales are smooth and arranged in 25 rows. (Wikipedia, general species account)