My glowlight tetras are sick and I'm not too sure exactly what it is or how I should treat it. It's a little hard to explain so I will include pictures. They seem to have potential fin rot as their fins have been slowly disappearing. Two of them have what looks like a white fungus around their mouth. I also noticed it looks like some of their scales have scraped off? The one that's in the worst shape has something weird going on with his gills. The look puffed out and like they're peeling. They're all loosing their color. They won't eat anything except for brine shrimp. My water parameters are fine so I know it has nothing to do with Amonia. Just looking to see if this is bacterial or fungal and can it be treated with melafix? I prefer not to treat with aquarium salt. Here are pictures of the worst guy. Hopefully this gives a better idea.