Little File Snake

The little file snake, also called the marine file snake or little wart snake, is found from India through Southeast Asia to the Solomon Islands. It is the smallest of the three members of the family Acrochordidae and the only one that permanently lives in estuaries as well as coastal seas. Completely aquatic and nearly helpless on land, it nevertheless has skin that slows drying out, which lets it travel out of water (Wikipedia, general species account).

The scales are spiny, giving a rough texture, and tubercles with nerve endings on the skin between the scales are used to feel water movements made by prey. The tail is compressed from side to side, and the snake can flatten its body to help swimming. It has salt glands under the tongue like true sea snakes, but is still prone to dehydration at sea and relies on freshwater lenses on the surface (Wikipedia, general species account).