"Starfish are carnivores and can feed on all kinds of invertebrates, especially shellfish, crustaceans, polychaetes and fish. There are also relatively small creatures, such as sea urchins and anemones. Starfish is the most representative echinoderm in structure and physiology. The body is flat, mostly symmetrical with five spokes, and the boundary between the body disk and the wrist is not obvious. There are prominent spinous processes, tumors or warts on the body surface. Starfish are carnivores and can feed on all kinds of invertebrates, especially shellfish, crustaceans, polychaetes and even fish. Some are monogamous. For example, many species usually only eat bivalves.

Most starfish have long and flexible wrists with suckers on their pins. Most of them feed on bivalves. When they eat, their bodies are on the shell and their wrists are sucked on both sides of the shell. Due to the vacuum effect of the suction cups at the ends of the pins, their pulling force is enough to open the shells of bivalves.

Starfish immediately digs out the stomach of the spout, inserts it into the mouth of the shell, secretes digestive enzymes until the adductor muscles and internal organs are partially digested and the shell is completely opened, and then the swallowed food is surrounded by the stomach and enters the mouth together.

Extended data:

Starfish have strong reproductive ability and a life span of 35 years. There are about 1500 species of starfish in the world, most of which are propagated by in vitro fertilization without mating.

The male starfish has a pair of testicles on each wrist. They excrete a lot of sperm into the water, and females also excrete thousands of eggs through the ovaries on both sides of their wrists. Sperm and egg meet in water, complete fertilization and form new life.