Last night she was last seen at the top of the tank nose out of the water and spinning on her tail. She was perpendicular to the bottom.
I decided at that time that she was definitely on the way out and decided on euthanasia. It wasn't an easy decision, but I think that the treatments, at the end were causing her more distress than good. RIP
Humblefish and Hedgedrew, thank you for your help and support.