Fin Rot? My husband has a 50 gallon saltwater tank. Up until about 3 days ago, he had  a black and green Nudibranch in the tank. Unfortunately, this poor creature  met his demise when he got sucked into the power head. I'm not sure how long he was stuck in the powerhead, but I came home and  noticed that everything did not "look right" with the tank. That is when we  found the Nudibranch and promptly removed him. At the time that we found  him, we also noticed that all of the fish were stressed and covered with what  looked like freshwater aquarium "ick." There are two blue/yellow damsels,  one domino damsel, one yellow tang, and a clown fish in the tank. At first,  the domino damsel seemed to have suffered the most. His fins were tattered  and bloody and he had a white "covering" on his eyes. Soon after, the clown  fish and one of the blue/yellow damsels were affected. The tang developed  clear, blister-like nodules on his fins (excluding the tail and dorsal fins). We have done a 25% water change and yet the "fin rot" seems to be getting  worse. The tang now has no flesh to speak of on his fins...there is nothing  left but bone...and his dorsal fin and tail are showing signs of infection.  My first thought was that the Nudibranch released a "poison" into the tank  when he was chewed up by the powerhead. Am I correct? If so, what action  and/or treatment can be done to clear this up before all of the fish are  affected and killed? The biggest problem is that my husband also has  anemones, tube worms, sponges, soft corals, and other invertebrates in the  tank. Whatever is in the water seems to be affecting EVERYTHING and we don't  have a hospital tank. PLEASE help us...give us some advice...something to  try! Thanks, Gina and Dane Gerdes >> How much made-up synthetic seawater do you have on hand... Change ALL or as much of the water as can be removed and replaced to have all your gear still working (i.e., if only half the tank can be refilled, but all your filters, pumps, heaters work, do so). Do you have any chemical filtrants like activated carbon on hand. Do place that in your filter flow paths... You've noticed how distinctive Nudibranchs are in "wild" photographs? And how slow moving they are in captivity? Yes they are bundles of noxious materials... as part of their involved defense mechanisms package...  Here's hoping that the massive dilution and absorption saves the rest of your livestock. Good luck to you. Bob Fenner

Starting aquarium for Nudibranchs or flatworms 9/24/04 I have a fish only tanks for a number of years. I am now interested in starting a species specific tank for Nudibranchs or flatworms. any web sites, books, articles, recommendations would be helpful. thanks mark <hmmm... both are rather challenging. The Opisthobranchs for their oft-obligate diet on inconvenient (to us) prey... and flatworms for much of the same (largely predatory too). There are some great Nudibranchs that can be cultured though... temperate and tropical... carnivorous and herbivorous. Check out some the fine ID books at Behrens seachallengers.com... and be sure to visit the seaslugforum.com on the Web. I have an article on culturing Berghia Nudibranchs in the January issue of reefkeeping.com if it interests you. Best regards, Anthony>