I have a 39gal tank with two JD's in it. One large male 6" or so and a female 4". They've been in the tank since around May 09. Both have been doing well. They have breed several times over the past few months. I do a 10 gal change of water every 2-3 weeks. Yesterday the female who is almost always in her cave was at the top of the tank breathing heavy and has what looks like fin rot or ich. It came on so suddenly! The male is perfectly fine. Before she was sick, I cleaned the filter (Eheim 2213) medium which I've done a couple of times since I got the fish. I did put new coarse filter pad and a fine filter pad in. The Mech and substate are the same. Once I noticed she was sick I immediately added a proper does of melafix. The instructions on the melafix says to treat daily for 7 days and then do a water change, which I plan to do. Is there anything else I should try? Any idea what might have cause her to get sick so suddenly and the other JD not to be sick at all? I've been feeding Cichlid Gold by Hikari. I'll post pics of her when I get home, at work now. Thanks for any advice or help you all can give.