No, the pleco seems fine, but it is in a tank w/guppies, one oh which shows symptoms of some fungus. Wah. Do I need to take the pleco out while I medicate the guppies? Thanks for the help!!!!
If your pleco isn't sick, don't treat him, especially with an antibiotic.
In fact, don't use antibiotics lightly. If possible, save them until they are really needed and then be sure to give the full course of treatment. This is recommended not only to be sure that the infection is gone, but to avoid having some of the bacteria that may survive unnoticed, from developing into antibiotic resistant strains.
Are you sure your guppies have fungus? Or, could it be Columnaris bacterial infection which is often mistaken for it?