So last night I noticed one of my female dwarf neon rainbow fish had this pink fungus-looking growth on her side, in the caudal peduncle (the area right before the caudal fin). She swimming okay, and eating still. Then this morning, I noticed the same type of growth on one of my dominant male rainbow of the same species. it doesn't seem to be affecting him at all either. The tank is borderline over stocked, I must admit. it's a 55 gallon dirted moderately planted tank with dry-dose fertilizers, medium light, etc etc. I've been slacking on water changes for the last few weeks (due to being busy with final school work and whatnot), and I brought a few fish from the aquarium I manage at school (for community service hours, which I need to graduate) into the tank. Now, I had no where else to put them, but all of these fish were bloated, from the students each period feeding them, I suspect. They could have brought something into the tank as well. Any suggestions besides my already planned daily small water changes, that I could do to combat whatever this is? Any suggestions as to what it could be? As I've never seen an infection like that before in my ten years of keeping aquarium fish o.o, thanks in advance for any and all replies