Most carideans are omnivorous, but some are specialised for particular modes of feeding. Some are filter feeders, using their setose (bristly) legs as a sieve; some scrape algae from rocks. The snapping shrimp of the genus "Alpheus" snap their claws to create a shock wave that stuns prey. Many cleaner shrimp, which groom reef fish and feed on their parasites and necrotic tissue, are carideans. In turn, carideans are eaten by various animals, particularly fish and seabirds, and frequently host bopyrid parasites.