Starfish is a star-shaped marine species whose types range between 1500 and 1600. In general, starfish have five arms and its colour varies from light as orange to dark as brown. Their ability to regenerate lost parts of their body makes them different from other marine species. Other than its physical appearance and functioning of different organs, marine biologists interest inclines toward their feeding behaviour as starfish lacks a visible mouth. The feeding behaviour of starfish includes stomach eversion and suspension feeding. Being a slow mover, the starfish feed on slow-moving animals or immovable species such as plants.
A numerous research done on this particular species found that starfish is a carnivore and consumes following organisms for nutrition and its survival.
- Microalgae: Microalgae is a most common diet of a starfish. They are unicellular organisms existing in groups or individually and found in freshwater and ocean. Also, they lack roots, stems, and leaves and is most suitable to the starfish digestive system.
- Sponges: Sponges are available in abundance on the sea-beds of all the oceans and thus, proves most accessible food to the starfish. They are the multi-cellular species that contains bodies full of pores, which helps in maintaining water circulation through their bodies to acquire food and oxygen and remove wastes.
- Bivalvia: Bivalvia is a marine mollusc that consists of a compressed body enclosed in a shell. A numerous variety of Bivalvia lives either in saline water or fresh water. Among all the Bivalvia species, a saline Bivalvia is a part of a starfish diet. Clams and Oysters, which belongs to different families of Bivalvia are common food to starfish as they are usually attached to the rocks and thus, are accessible.
- Snail: Snails are the species found on the land, sea and in freshwater depending on their kind. Their coiled shell distinct them from the other marine species. Starfish consumes snails, not in abundance but only when it found them.
- Coral: The starfish such as crown-of-thorns feed on coral. Coral is a marine invertebrate that lives in colonies of identical species. A coral’s common habitat is tropical oceans.
- Small animals: At times, starfish eat injured fishes, which are unable to move faster. As the injured fishes’ inability to move makes them a reachable prey to the starfish.
- Decomposing plants and animals: Though known as powerful hunters, starfish at times feed on decomposing plants and animals and fecal matter found in the water or on the beach. This eases their hunting episode but such feeding provides low nutrition to their body. Such food, at large, confines to the detrivores starfish.
Also read: What do Goldfish eat?
Other than consuming organisms, starfish possesses the ability to absorb organic nutrients from the surrounding water. When starfish is unable to find a prey, this organic nutrients consumption form a significant portion of their diet. As there are twenty thousand species found under the category of the starfish, their eating habits and specific food choice depends on their body type and internal system. A common feature in all the starfish includes their behaviour of an opportunistic feeder, slow-moving food, and eating marine organisms.