I’ve had a guppy that has been somewhat unwell for a couple months now and I can’t for the life of my figure out what it is. I’ve tried treating it for swim bladder, white spot, fungal/bacterial infections you name it I’ve bought treatments for it. I’ve tried salt baths and a hospital tank and she does not seem to be getting any better. The past few days I’ve noticed a chunk of her tail missing again and she now seems very weak/limp and has gotten quite skinny. She also has been struggling to swim and seems to be floating vertically and just being pushed around by the filter etc. PH level is 7.1 and no traces of ammonia,nitrates etc as I tested the water yesterday and did about an 80/90% water change the other day. I feel like it may be a bit too late to really save the poor thing but any ideas as to what it could be as no other fish are unwell in any way.