I’ve been keeping cardinal and neon tetras for quite sometime now and eventually got many cardinal fries. However, It seems like no matter how good the water qualities is, these fish will eventually contract the “Neon tetra disease” at one point. The symptom includes cyst growing on their mouth and curved spine seems to be untreatable. So I’m curious to know what caused this disease and I’d like to hear you guys experience on keeping cardinal or neons.