OK...I have a betta in a one gallon tank with no filter/heater. He developed a whitish spot on his head that has now proceeded to eat him. He has a giant hole in his head that I have treated with everything I can think of (not all at the same time of course) Pimafix because at first it looked cottony, then Melafix because the previous did nothing. When Melafix did nothing I treated with an anti-parasitic that has also done nothing. The hole just keeps getting deeper into the muscle and I am afraid it is too far advanced. I have been doing 25%+ water changes every few days. This has lasted for weeks and won't seem to let up. I can try to get pictures later. Any advice?