hi there get it out of the tank if possible,angels get what is equivilant to aids but because it's eating well, that is a really good sign.
They can get really agressive when wanting to breed and the female can get pretty ripped up from it . the slime things got me beat! i find they do well in soft water and if you can get you hands on catappa leaves chuck them in the tank, they,re good at bactarial probs and parasite probs too, also check their poo if it is white and stringy, the whole lot need to be wormed.
Also i thought i'd better warn you that when you stick the indian almonld leafs in ,there will but one massive orgy as it's promotes breeding, so more fights could be on the horizon, i find they best way to avoid the males getting rough with mum is to simply sratch the eggs off and get rid of them out of the equasion.finally even though your kh is reading ok(that's) if it is you calcium could be low but the test will be lieing in a way, cause it measures the hardness not just the calcium and so won't give you specifics, seachem replenish will fix that prob so there no osmotic shock, but you'll have to act quick. other wise get onto seachem support there are wonderful and know everything.