be careful, this is very infectious, could spread to other fish. My entire store was nearly wiped out, twice due to datnoids with "pimples" and so the some customers that had the same problem.
I coined the term datnoid disease since it came from some new guinea datnoids back in 2002 or so. starts off like a slight pimple, and whether you pop it or not, it will spread, and then attack the gills, the fish will breath heavily, then stop eating and die within days. some fish are however immune to it, lived with them and showed no signs whatsoever. I've spoke to several ichthyologist and microbiologist background people and they think its viral, hence the rapid spread. then they get secondary infections, non healing wounds which would be more likely bacterial. look up mycobacterium marinum. non healing ulcerations
good luck guys...