Dropsy in Oranda Goldfish

So one of my orandas has dropsy, I'm pretty sure at least. From what I see it is difficult to cure the fish and has a low chance of living. I was thinking of setting up a medbay tank to see what I could do but don't exactly know what I would need for the tank, any suggestions? I have medications on standby but I will be heading to the store for more if needed.