I recently got in a super nice monti colony and with in a few weeks part of it had appeared to RTN. I thought nothing of it, just figured it was stressed from shipping. Well I went to frag it up because a big chunk of it was now gone. While fragging, I noticed some nudibranch's on it and turned out to be monti-eating nudi's!!! So it didnt RTN, it had been eaten!!! Well I inspected the rest of my monti's and now they all had them!!! Anybody who has been around this hobby and heard of monti eating nudi's know you can kiss your monti's good bye. I was told about an article wrote by Eric Borneman experimenting with Potassium Permanganate and the success he had with it. Though his experiment was very small and limited, he did lead the way for me to experiment with it. Two Potential Molluscicides Useful Against Pest Aeolid Nudibranchs Common on Species of Montipora in Aquariums by Eric Borneman - Reefkeeping.com This stuff is WILL kill the nudi's and dissolve their eggs. Here is how I did my less then scientifical experiment, but easily replicated. First you have to acquire some Potassium Permanganate. Its real easy to get it because it is used in explosives, but there are versions of it used in various other fields. I picked mine up from Tractor Supply Company. You can order it online, but be prepared to look for a place that will ship it to a residence but it is a hazardous material. I bought PRO Pot Perm, Greensand Iron Filter Regenirator. Its used to oxidize Iron and Manganese to where it can be filtered out of water. There are other products out that contain potassium permanganate, but you wanna use the purple crystal kind. I used a specimen cup(urine sample cup, I use them for frags at frag swaps, much easier then bagging them). I added 50ml of tank water then I added 1/8 teaspoon of potassium permanganate. I stirred for 1 min and then let it set for 20 mins to insure it fully dissolving. I used a plastic container measuring 12x6x4" and added around 9-10 cups of tank water to it. Then I add 5ml of the dissolved potassium permanganate and tank water to the plastic container. I put the monti's in the plastic container and let them soak for 15 mins and then using tongs, I shook each piece to rid the corals of the dead nudi's and then let them soak for another 15 mins and shook again and then rinsed them off in another container with tank water and placed them back in another tank free of nudi's and eggs. I just dipped all of my monti's and they are now nudi free with no visible egg sacks. on a side note, it will turn your corals brown, but they color back up... NOTE: USE THIS AT YOUR OWN RISK, I ASSUME NO RESPONSIBILITY FOR ANY CORALS DIEING OR INJURY TO YOU OR OTHERS. MAKE SURE YOU READ THE ENTIRE LABEL ON THE CONTAINER OF POTASSIUM PERMANGANATE BECAUSE IT CAN AND WILL DISSOLVE ANYTHING ORGANIC, YOU ARE ORGANIC! Montipora eating Nudibranch Montipora eating Nudibranch with egg sacks.