Clownfish will definately be attracted to a goniopora. However, gonioporas have a poor record of survival in the aquarium and some say that the resident clown will eventually kill the goniopora by causing it to keep its tentacles retracted. I had a pair host a goniopora for over a year with no sign of deterioration of the coral. Clowns may also host a condy anemone (which is easier to care for than clownfish-hosting anemones), hairy mushroom, toadstool leather, elegance , frogspawn, hammer, or anchor corals.