I tried posting this a couple times before and it's not working but basically my black moore goldfish lost an eye and I don't know how. I currently have him in a 5 gallon hospital tank with melifix and aquarium salt in the water, is there anything else I should add or do to help my fish get better? He is eating and swimming normally and used to be housed in a small pond in my backyard with one other faintail goldfish.

He should be fine, just keep the water clean until he heals (regular water changes).
I have had fish with all sorts of problems over the years, including missing eyes and they have all survived. I actually had one goldfish with a mouth deformity who lived quite a few years. One whole side of his mouth caved in, it looked like a crescent moon when he opened it. I just had to make sure the food was crushed up a bit smaller for him.

Are there any other fish in the tank with him that could cause him problems? I would probably keep him separated for now if there is so there others aren't tempted to 'peck' at him.

Ok, Thanks