no, I would think not. most clownfish will cause the demise of a flowrepot, but this is usually gue to hosting issues. I have seen many clown "mouth" or "bite" on coral polyps. sometimes from their host and sometimes from another coral. hard to say what the determining factor is. could be anything from and infection of the mouth to another one of the clowns unusual quirks. I would try moving the coral to another part of the tank. I know this will stress it even more, but hopefully the clown will not follow it.