Columnaris or fungus. How to tell?

[Abbitha]

Alright so one of my neons has had this cottonmouth going in for a few weeks now. Like a month. Then my angel fish developed a white cyst ball like thing by his dorsal fin 2-3 weeks ago It ruptured and then a bunch of tiny little white balls started growing in the sore. They have since ruptured too. His breathing is a little heavy. And his right gill actually expands more than his left gill if that makes sense? I've since noticed my betta has a little bit of white patch on his head. It's actually hard to tell if it's his coloring or not but to play it safe I took a picture.

What do I treat for. I dosed Pimafix and melafix and the angelfish is actually getting better. His white dots are gone and it just looks like an open wound now. But it has had
No effect in the cottonmouth. And the angelfish is still breathing harder than normal. I need medicine that is SAFE FOR SNAILS AND PLANTS! and won't hurt my nitrogen cycle.