Exactly! It is a symbiotic relationship between the anemone and the clownfish. The anemone is the host. The tentacles of the anemone sting most fish. However, the clownfish is immune and thus uses the anemone as a host / house. They guard their host with serious aggression. My dad"s clown will physically bite and draw blood if you get your arm to close to his anemone while cleaning the tank, but we love him any way.