This is a mutualistic symbiosis, in which both organisms benefit from the relationship. The clownfish cleans the anemone, and feeds it to some extent (anemones are largely photosynthetic, thanks to a symbiotic relationship with photosynthetic algae, but will also eat fish, invertebrates, and food particles dropped by the clownfish), and the anemone gives the clownfish a safe place to call home.
