Question

A clownfish and a sea anemone what relationship is this ?

Answer 1

Clownfish have a "symbiotic" relationship with sea anemone. Meaning they benefit from living with the sea anemone, and the sea anemone benefits from the presence of the clownfish.

Answer 2

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.