Nu-Nu the eel said:Those are called apista. Kill it because they can sting your coral. Use boiling water or lemon juice
Chrisbmilton said:Ok thanks guys, I was reading up on it - and it's Aiptasia I think it's spelt. I read that peppermint shrimp keep these under control?
If you're not careful the aiptasia will self replicate, any cell from the disc section can become a new one. Be careful with the shrimp too, it has to be Pacific (or Atlantic? I forget, either way one of them works, the other doesn't) and once its done with your aiptasia it will go for your corals. Same for a butterfly, although you do find some that won't.