Clown attacking favia

[Chiefstrum]

I've had my tank for about a year now and I have two ocellaris clowns a royal gramma a bangai cardinal and a gold head goby. I also have several favia some hammerheads mushrooms and zoanthids. Everything has been going well except today one of the clowns started burrowing into a favia. Maybe it's trying to host I'm not sure. In any case the same clown keeps fighting with the other clown and the gramma. Any ideas why it would turn aggressive? Also is there a way to dissuade hosting? After several runs the favia expelled all this red stuff in a cloud. I think it was probably just when it expelled water in a burst but I'm not sure. Any ideas? Sorry for the poor punctuation etc. I'm on my phone.