Found this on a colony of my Zoas, I freshwater dipped them for 3 minutes when I saw him before ( a couple of weeks ago ) but I was fragging them today and it looks like he survived the dip. Anyone have any pictures of any confirmed zoanthid eaters?
Yup. Aeolid nudibranch - coral muncher. You'll need to FW dip it every day or so and inspect for eggs, larvae, etc to be sure you get them all. http://www.reefkeeping.com/issues/2005-05/rs/