Anemonefish
are most often found living in a symbiotic relationship with a "host
anemone". The fish is immune to the lethal sting of the tentacles,
due to a mucous coating that fools the anemone into thinking it is part
of the host.
When
threatened, the fish darts into the lethal protection of the stinging
tentacles. But by actively swimming around in the tentacles, the fish
creates additional waterr flow, increasing the amount of food the anemone
can trap from the drifting water.