just an update - he spent the day yesterday hiding after the move to the hospital tank and didn't eat. Today, he's out swimming around bit. I'll be feeding the fish in a few minutes so I'll see if he continues to eat. His condition does not seem to have worsened, so that's good. I have not settled in on a treatment yet since I've still not sure what I'm dealing with. So for now, I'm just going to observe.