Powder blue-Fin & tail rot, stop eating

[CoppBandbuttfly]

Tried Pimafix, Maracyn-two respectively in the past few months, both did not work. Fin and tail rot been a few months, still active but stopped eating around two weeks ago.

5 days ago I put it in a hospital tank(10 gallons) and started using Melafix Marine...it seems a little bit improvement on fin and tail rot but still not eating. Fish size is medium to large. I like this fish a lot and really want to save it.

Pls help on how to make him eat again. Water parameters are all stable and good.

Thanks.