sick pyramid butterfly fish

[AquaAddict]

It has a slighlty ragged tail and a couple of white spots (1 on tail and 1 on dorsal fin) that won't go away after two weeks of Furan 2. It had a white mouth but that has disappeared.

I tried ParaGuard today and the fish turned black after a few hours. Can I lower the dose and still get rid of those two white spots and get that tail growing back? I am thinking it might be fungus instead of a bacterial infection.

AquaAddict