I have one goldfish and all of a sudden during the last 3 days his fins have gone black but his body is still golden what's happened please help thanks

I THINK that means there isn't enough oxygen in the tank.

I think this might be ammonia burns... it should fade. Have you done a tank change recently? If not check your ammonia levels... it will burn the fish and their fins turn black. It's kind of like dead skin coming off.

Actually, this is normal in goldfish.
It's their pigment. It happens to some and not others.
As he grows the black will turn back to the original color.

Actually, this is normal in goldfish.
It's their pigment. It happens to some and not others.
As he grows the black will turn back to the original color.

I've never had gold turn to black, but have had black turn to gold :) The black fins is what I was worried about... when they change isn't usually their body first?

It really depends on the fish.
Black moores are the only ones that I know of where their body
Will turn black to gold.
Usually in the common goldfish (commonly know as feeder fish) the first
Signs will begin in the fins (or some of the fins),
Then body, then they go back to gold as the black fades away.
But I'm sure there have been cases where the pigment in the body changed first, and cases where the fins were not effected at all as well, it's just not as common.:)

Thanks for the clear up Kae! :)

Got to be sick