Thank you so much!fluttermoth said:Hi there,
Sadly, I definitely think that looks cancerous![]()
You could try treating the fish with an antibacterial medication, like Escha 2000 or Myxazin (I'm in the UK, I'm not sure what medications are available to you in the US); don't bother with Melafix or Pimafix though.
Apart from that, there's not a lot you can do except euthanize the fish if you feel it's suffering; we can advise you on humane methods of euthanasia, if you get to that point![]()