A number of sea anemone species are commensal with other organisms. Certain crabs and hermit crabs seek out sea anemones and place them on their shells for protection, and fish, shrimps and crabs live among the anemone's tentacles, gaining protection by being in close proximity to the stinging cells. Some amphipods live inside the coelenteron of the sea anemone. Despite their venomous cells, sea anemones are eaten by fish, starfish, worms, sea spiders and molluscs. The sea slug "Aeolidia papillosa" feeds on the aggregating anemone ("Anthopleura elegantissima"), accumulating the nematocysts for its own protection.