My Clarki clownfish decided that it really liked my beautiful goniopora. It has created a problem in the fact that she is causing the goniopora not to fully extend because it always swims through it but thats life
Thats sucks, my LFS has a pair of clowns in their DT hosting 2 or 3 gonis and they all still fully extend. You should try putting something like a hairy or toadstool mushroom in the place where your gonio is, and move it and maybe the clowns will start hosting the softie.
You can also cover it, if it's not too big, with a plastic tomato basket from the grocery store and the clowns will move on to something else to host. Be sure to wash the basket throughly first.
ive heard that when most peoples clowns start hosting corals, they are bothered by it and dont open for a while, but most of the time, they end up becoming used to it after a couple weeks of being hosted