Rescued a carnival goldfish and want to set up a container pond.

[j.w]

He's a pretty little fish and will get that nice white and oj color more distinctive as he grows. I have a couple like that and a couple that are completely white and then all the rest that are mostly just oj or still trying to turn from black to oj.
That black on the fins could be ammonia poisoning from his previous home at the carnival. Maybe now that he's in a better environment it will go away.