silver dollar scare

Question
I just bought 6 silver dollars, I've always had African cichlids but decided on something different they are in a 55 gal tank I just checked everything ammonia,temp,hardness ect and it is like it is suppose to be, my problem I fed them around 9AM I did notice one had some torn fins I just came in around 9PM went to feed all my babies got to the dollars tank and they look awfull like there tails have rotted there dorsal fins are gone on one and i have one that is still o.k. I read up on them and took the charcoal out and treated the tank with melafix I hope I've done the right thing  but I was a little worried. I would appreciate any help you could offer. Oh I've had these guys for 4 days they are in the tank with two 3inch spotted catfish

Answer
Hello Denise:  I found this question in the general pool of questions and thought I would give it a try... It sounds to me like you might have fin-rot disease. Malafix is great for open sores, etc but fin-rot is more of a fungal/parasite issue.  Raise the temperature to about 80-84 degrees and add aquarium salt.  You will also want to start with an antifungal medication...visit your local aquarium they should have a large selection of adequate medications.  Make sure you tell them you want the meds for fin-rot... please keep me posted on their condition... dave