Not to be harsh but this is what I call "new guy" disease! Even if the "new guy" has had the tank for years, it shows a lack of experience when we ignore our maintenance until we see a disease. With more experience, most will determine it is far better to do the routine, necessary, drudge work to keep the tank conditions better so that we avoid the trauma of trying to treat disease as they will certainly show up.
The time spent deciding what disease and how to treat it on the odds we might be successful is much better spent doing the work needed to avoid the disease in the first place.
Better use of time, better use of money! Your meds probably cost almost as much as your fish, didn't they?