The Snake Sea Stars are a large family of sea stars, named after the slender members of the genus Ophidiaster, which have snake-like arms. Many species are brightly coloured and patterned, mimicking the appearance of other marine animals which may be poisonous or dangerous for protection.
Some species have remarkable powers of regeneration, allowing them to shed and regrow arms, or reproduce by shedding an arm which then generate a new disc and arms to form a new individual. The Linckia genus is prayed upon by Harlequin Shrimp (Hymenocera picta) and can completely regrow lost limbs.
Snake Sea Stars have several rows of tube feet on their underside which can be used for movement, sensing their environment, and detecting food.
The Blue Sea Star is very common, seen at all dive sites around Koh Lanta. This sea star normally has five long, thin arms extending from the small central disc, with rounded tips at each end. The arms are covered in numerous closely packed lines of faint, slightly raised spots.
The Blue Sea Star grows to 30 cm and are found in shallow water exposed to sunlight, either singly, or in groups. This sea star can be found on the sand or rubble bottom, on rocky walls, on corals, sponges, just about anywhere in the reef area. The diet includes organic matter, dead animals, small invertebrates and anything else tasty that comes their way.
The Red Star has a small central disc and 5 thin arms which taper toward the end. This species has a very similar shape to the Blue Seastar.
This species has a variable body colour, from cream to grey to brown to red and pink. The body is covered with red spots and many small granulations. A Red Star can grow up to 13 cm in diameter.
The Red Star is capable of self amputation) and often sheds one or more arms, which can then grow into a new individual. The arm detachment process takes up to an hour, with a small crack appearing on an arm, approximately 2.5 cm from the disc. Once the crack has appeared, the tube feet on the arm and the body pull the two parts in opposite directions. The detached arm is known as a 'comet' and moves about independently. It takes about 10 months to regenerate a new disc.