The clownfish will be hosted by whatever their little hearts desire, be it a coral, powerhead, corner of the tank, heater, patch of algae etc. If you buy something for them to host there is no guarantee they will be hosted by it.
Clowns really do just like whatever soft fuzzy thing you put in there so dont bother with an anemone unless you have your heart set on it its a lot of trouble.
LOL, yeah, Clowns are retarded. I have a female that will hoat a huge Toadstool leather at night. And the male, his ass got kicked to the curb and he will dig himself a little bed in my sandbed every night.