Man have I lost some apistos in the past to this very thing. I'll tell you what works for me but keep in mind I keep all my apistos in 20 gallon longs with leaf litter for substrate and one school of dither tetras per breeding tank very few live plants. For my apisto caca. I keep my tank at 77F pwc once a week 50%. The disease in question is a combination of bacterial and secondary fungal infection usually brought on by water quality issues,poor diet, too much carbon in the filter, vitamin deficiency or fighting or rough breeding. Also newly introduced fish could have brought the disease in not saying any of these apply to you just merely a basis to go on from my years of keeping these guys. With that said only combo that ever worked for me if disease is caught in time is herbtana and artemiss used in combination both made by microbe-lift. Both are natural organic treatments that won't cause bloat in apistos like other stronger meds do. Maracyn one and two also have worked for me in the past as well. I find the first two mentioned a bit easier to use on these delicate gems so it's up to you. But keep up water quality and add liquid vitamins(vita Chem) to their foods which can help out alot. Also aquarium salt can help if the other meds don't but keep an eye on them if treating with salt apistos vary in how much salt they can take, if you notice problems change water ASAP and discontinue the salt treatment. And I just have to say the obvious always remove the carbon if you even use any during treatment of meds. I hope this helps if I left anything out I'll think of it and get back to you any more questions ask away please I hope she pulls through.(fingers crossed)