star polyps although if you couldn't see the purple mat like Crox pointed out I might have also guessed anthelia, they are very close. I would also say peel them off and move them. I made the mistake of allowing my neon green and greenish yellow star polyps to spread and now I have lost a few frags of corals from them stinging or just irritating the crap out of them. They grow fast enough a little trimming won't make much of a dent.