The Blue-Ringed Octopus can be best described as ‘one cute animal that might kill you’. What do sea stars eat, and what its a sea star. Commonly many whales are known for feeding on krill and other tiny crustaceans, but many are left wondering: Do whales eat fish or octopus? In the home aquarium setting, the Blue Linckia Sea Star prefers a well-lit sandy or coral rubble substrate, with many rocky hiding places. The Blue Linckia is also prone to parasitization by a species of the parasitic gastropod Thyca crystallina. Most starfish, also known as sea stars, eat by prying open the shells of prey such as clams or oysters with their arms, pushing their stomachs out their mouths and into the prey's shell, partially digesting the animal and then pulling their stomachs back into their mouths. Many sea stars eat mussels and clams in an interesting way. To us humans, starfish look like they’d be a bit too hard and crunchy to make a good meal. Sea Star Care.