Starfish

Starfish are also called sea stars due to their five-arm shape, but they are not a species of fish. A healthy starfish has five or more arms that branch out from a central disk and has tough skin with sharp, calcareous spines. They can sometimes lose an arm, which eventually grows back.National Geographic: Starfish Profile

Starfish eat small fish, oysters, clams, sea urchins, mussels and arthropods. They consume food by moving their stomach through their mouth and into the shell of their prey, which they grab with their suction-cup-covered arms.National Geographic: Starfish Profile