Starfish grow up on crustaceans, shellfish, fish, polychaetes and invertebrates. It is a carnivorous animal, and its wrist can be bent and has suckers on it, so it can be used to open the shell of shellfish, and then secrete digestive enzymes to digest the meat inside, and then swallow it into the mouth. In addition to this way, some starfish with short wrists can swallow the whole food and digest it in the stomach.

1. Shape: Starfish has a unique shape, flat body and five-radiation symmetry, which looks like a five-pointed star. The boundary between its body disk and wrist is not obvious, and there are tube feet on the wrist, which is convenient for it to move. It is worth mentioning that, as an echinoderm, it is far from the sea urchin, sea cucumber and sea snake tail of its kind.

2. Eating: Starfish also eat in a special way. It mainly feeds on shellfish. With the help of a bent and adsorbent wrist, it can easily pull the shells apart, and then secrete a digestive enzyme to digest and swallow Berry's meat. This way of digestion in vitro is also rare.

3. Regeneration: Starfish also has certain regeneration ability. Cut it into several pieces and throw it into the sea. Each piece will grow a lost part, which will become several new starfish. Different species of starfish have different regeneration abilities. Some need to keep a centimeter wrist, while others only need a piece.