For a while now, I've been treating my dwarf gourami for what I thought was ich, using protozin. He's only had three or four spots on him that I can see, one of which has now disappeared. However, the very first spot we noticed has never gone away. It's on the side of his body, unchanging, and it's been probably at least a month, maybe more, since we noticed it. He has displayed no signs of flashing or other unusual behaviour. No other fish show symptoms at all. Some of the spots on the gourami are very hard to see and might not be ich spots, but this one single original spot looks like the classic description of ich. I'm beginning to wonder if it's not ich at all but a damaged scale, or dwarf gourami disease or something. But then there was at least one other spot that came and went. Why is this one spot not going away?