Starfish
Starfish have a complete digestive system with a mouth centrally beneath and an anus on their upper surface. Food can be brought into the stomach through the mouth or, in many species, the cardiac stomach can be extended out through the mouth to digest food outside the body. Suspension-feeding starfish use their tube feet to pass food to the mouth. The cardiac stomach is connected to a pyloric stomach, which in turn is connected to both the anus and to the pyloric ducts and pyloric cecum which extend out into each arm. The digestive glands and the cardiac stomach produce digestive enzymes for the starfish to break down the food more easily. Starfish are also able to use their water vascular system to convert its stomach into crustaceans, allowing it to eat its preys inside the shell. Starfish generally eat smaller crustaceans such as, clams, mollusks, oysters, coral in the reefs, and some eat other sea stars