Disease of pleco

Question
my tank has been set up for two years.  It's a 55 gallon tank with two filters on it one is a bio-wheel and the other one is a double filter that came with the tank.  At this time there is only one 12-13 inch pleco in my tank. I change the water bi-weekly usually 1/3 of the water is replaced.  We use well water and the levels are all very constant.  He is eating well.  About a month ago he got a sore on the end of his nose it looked like gray and the skin looked sore.  I treated the tank for a week with melofix then did a major water change of 75% of the water and cleaned filters.  It looked better but not 100% and now there is what looks like a blister on the end of his nose - my husband says it looks like a wart but I say blister.  I have kept him isolated in the 55 gallon and don't know if I should treat him again with Melofix or an antibiotic as I'm not sure what's wrong.  Help please he's about 4 years old and his name is Alice.  thanks for your help CeeAnn

Answer
Hi CeeAnn;

He probably injured himself somehow. Unless it's reddish or fuzzy like it's infected, he's probably healing up and it has now left a callous (thickened patch of tissue).

Or, it could be a blister from rubbing against the aquarium heater. They get VERY hot to the touch, even underwater. I've seen heater burns before in many larger fish, sometimes with very tragic results. For some heaters you can buy a guard that prevents fish from getting too close. Or, you can make one from fishing line (use it like thread) and plastic craft mesh. Just don't let the mesh or fishing line touch the hot part of the heater. You make a sort of "cage" around the heater by forming a tube with the mesh and "sewing" the edges together with the line. Fasten it to the edge of the tank or the top of the heater in such a way that it hangs down around the heater. Craft mesh comes in many colors, even camouflage. Just rinse and use.

Or, he might be rubbing his nose repeatedly on something on the tank trying to dig a place to hide. If he doesn't have a cave to live in, provide one for him. Smooth stacked rocks, PVC pipe, or a large terra-cotta flower pot on it's side would work nicely.

At Your Service;
Chris Robbins