If the area where you see the growth wasn't "injured" (i.e. damaged in a fight or by running into some rock or something in your tank), then I think the odds are much greater that it is columnaris than it is a fungus. Columnaris is a bacteria (gram-negative flexibacter) which looks very much like a fungus. It takes many forms, one of them where it starts on the top of a fish and the infection gradually spreads down the fish's side, almost like a saddle on a horse. In this form, it is often given the common name "saddleback disease."
IF that is indeed what your ram has, then MelaFix (antibacterial) will be more effective than PimaFix (antifungal). Though realistically speaking, unless you catch the infection very eary and have a particularly hardy fish--and particularly weak strain of columnaris--neither is going to work.
I just had 5 dwarf neon rainbowfish with columnaris (though in the form of mouth "fungus"). I tried a combo MelaFix/PimaFix treatment, no luck. Switched to a combo of Maracyn and Maracyn-II (both broad-spectrum antibiotics), no luck. Then went to Kanamycin (another broad-spectrum antibiotic),which managed to kill all the bacteria in my filter
but still was unsuccessful in treating the infection.
In the end, I lost all five of those fish.
Good luck to you. From what I have read, columnaris strains vary incredibly in their severity. Hopefully your ram has a weak strain and you will be able to get rid of it.
P.S. -- If you want some good news, almost *all* of the "success stories" I have heard of people treating columnaris had to do with when it struck in this saddleback form. I suspect that is because the infection is almost entirely external. In the case of the mouth fungus, eventually deep lesions develop in the mouth area (it basically starts eating away the flesh by the mouth), and so the infectin is really rooted deep internally in the flesh of the fish--which means it is much more internal, and harder for a waterborne antibiotic to get to the main source of the bacteria.
