My first impression when I saw the photos above was columnaris. In some species especially in cool water, it presents as fungus like tufts, in some cases (primarily in warm water) as a swollen, extended mouth.
I have found, as the disease progresses the fish tends to hover in one area, and may try to eat, but can't.
Raising the temp is the worst thing to do, because the bacteria that causes columnaris reproduces exponentially as temp rises.
It can also easily be transferred tank to tank, by any shared equipment (nets, scrapers), or even hands.
I usually euthanize the heavily infected fish, then thoroughly vacuum the tank, and treat with hydroden peroxide to rid the tank of any residual bacterial populations.
The bacteria thrives in detritus, and there is a theory that high nitrates allows it to more easily infect the fish.