an animal that has adapted to life in flowing water (rivers, streams, and marine shallows that are washed by tidal or constant currents). Some rheophile animals spend their entire life in flowing water; others inhabit such waters only during certain periods (for example, migratory fishes and the larvae of caddis flies, mayflies, and other insects). Rheophile animals are oxygen-loving and need a constant inflow of fresh water. Some are good swimmers, capable of overcoming strong currents (for example, many Salmonidae). Many are sessile or only slightly mobile: they withstand the drift of the current by growing onto a substrate (for example, sponges and bryozoans), attaching themselves by means of body processes (for example, unstalked forms of sea lily) or by suction (for example, the mollusk Ancylus). Some rheophile animals hide in burrows or among rocks. A number of rheophile animals have adaptations for filtering water and catching food particles brought by the current.