Sea snake
Most sea snakes grow to sizes between 1.2m and 1.4m, some can reach 2m or more. Hydrophis cyanocinctus reach 2.5m to 3m. They reach a weight of about 0.8 -1.3 kg, at a size of 1.8m. In most cases, females are larger than males.All sea snakes have paddle-like tails  and many have laterally compressed bodies – they look somewhat like eels. However, unlike fish, they do not have gills and must come to the surface regularly to breathe. Nevertheless, they are among the most completely aquatic of all air-breathing vertebrates. Among this group are species with some of the most potent venoms of all snakes. Some have gentle dispositions and bite only when provoked, while others are much more aggressive.