Sorry to hear about your fish. Glad to hear the other one is doing much better. I think you should do a water change on the hospital tank especially if you don't have any kind of biofilter on it. So, in the picture, it looked to me like the skin was kind of melted or indented in, that's why I thought it a wound. I take it that, in reality, the stuff was sort of piled up on the skin? Or did they really have wounds and then the fuzz set in? Didn't it appear to be a fungus type substance growing over the fish?
I am pretty sure that the first picture I posted was just a wound, but I think the wound gave the infection a chance to take hold. Since my water quality was very poor with the large NO2 spike surly all my fish were stressed, and therefore had a reduced immune systems. When both Plecos got injured it set the stage for the infection. The rest of my fish including other Plecos that did not get injured, have thus far not contracted anything.
Anyway I did a large water change yesterday on the hospital tank, and I just went and looked at the Pleco still in isolation, hoping to move him back into the main tank today. It appears he is still infected and it is starting to spread again. He has a largish white sport on his belly about the size of a dime, and also smaller white spots sprinkled over the rest of his belly. It may also be on his tail a little bit. It does sort of resemble a fungus as it appears to be a white powder on the skin, however on close inspection it does not have the "hair" you would expect on a true fungus. I diagnosed it as columnaris due to similar appearance and also because I have read that many mistake it for a fungus but to check for the "hair" to be sure. I am now however starting to second guess my diagnosis, the Maracyn and Maracyn Two did fight it back quite efficiently, should I start a second round of treatment or should I try something else? Should I switch meds entirely or add something in addition to Maracyn and Maracyn Two?
I really hope I can save this guy, I already lost the ~10 inch Pleco, this guy is almost 8 inches and my next biggest is barely 3, in a 120g tank he looks like a minnow.
Attached is a picture of the Pleco in isolation, unfortunately the picture did not turn out very good due to glare.
