Sea Stars or Starfish are echinoderms, with around 1,500 species occurring on seabeds of every ocean. They live in the tropics through to the polar regions, and can be found in shallow rock-pools down to abyssal depths. They are an ancient group of creatures dating back 450 million years, with a range of extraordinary adaptations including hydraulically operated tubed feet, regrowing damaged body parts, shedding arms for defence, and everting their stomachs to digest prey much larger than their mouthparts. Most starfish consist of a central body disc and five arms, but some species have multiple arms up to fifty in number. Seastars come in a huge range of sizes, shapes and colours, and although they have primitive sense organs they are sensitive to temperature, light, touch, and the water conditions around them. Their abundance makes them a ‘keystone species’ ecologically, playing a critical role in the health and balance of their environments.