Eric Borneman recently published a very nice article in Reefkeeping Magazine, entitled Two Potential Molluscicides Useful Against Pest Aeolid Nudibranchs Common on Species of Montipora in Aquariums. Of particular note within this article was a description of the effectiveness of potassium permanganate dips as a method of eradicating aeolid nudibranchs without overly stressing coral tissue. You can find the text of the article here.

Potassium permanganate is a staple chemical in the aquaculture industry. It has been widely used as a method of removing oxygen-consuming dissolved organic chemicals from water, increasing oxidation-reduction potential, and controlling nuisance hair algae. It is also used as a dip for removing parasites from freshwater fish. We use it regularly for treating rapid tissue necrosis (RTN) in corals and preventing bacterial infections. It is also highly effective at removing other pests, and now it seems that it has potential for removing both the adults and egg masses of coral-eating aeolid nudibranchs.

Care should be taken whenever one is using potassium permanganate. An overdose in a reef tank will quickly kill every inhabitant. Treatment for ectoparasites, rapid tissue necrosis or aeolid nudibranchs should always be performed as a separate dip, never in a display aquarium.

Arizona Aquaculture Solutions produces our own line of aqueous potassium permanganate for home aquarists to use. Unlike the dry form of the chemical which must be shipped as a hazardous material, aqueous potassium permanganate can be shipped without difficulty.