Starfish are not really a fish, it is an echinoderm and it is related to the sand dollar. Echinoderms have bony skin to protect them. Most starfish, such as the Bahamian Starfish, have five arms and can live up to 35 years. They have no brains, or blood or bones and they breathe by filtering sea water.
Most people think starfish are slow and passive but they are actually a very aggressive predator under the sea, hunting mollusks and other echinoderms. Starfish turn their stomachs inside out to eat. Its stomach is like a thin rubbery transparent bag, which it wraps completely around its prey, until the prey is digested.
Cool Fact: If a starfish loses an arm, it can grow a new one.