Sounds like the same problem I had, but you can get those symptoms from a variety of diseases. Mass-production fish breeding has caused lots of problems for us fishkeepers. The store doesn't mind, since we'll buy $20 worth of meds to save a $4 fish!
I can't say for sure that you have the exact problem I had. See this thread for how I treated my tanks. http://www.tropicalfishkeeping.com/t...-advice-69258/
BUT usually you do not
want to blindly treat a tank for a disease. That can cause other problems. You may want to try a more easily administered product like Jungle's Parasite Clear. I have never used it, but it treats a variety of internal parasites.
Good luck and don't let this type of thing discourage you. It's unfortunately pretty common and no reflection on your ability to keep fish
Also - a belated welcome to the forum!