Bubble eyed goldfish with black back?

[audiman]

One of my bubble eyed goldfish has developed some unusual black markings on its back. The fish doesnt seem to be affected in anyway, still feeds and swims about loads. Just wondered what it is. It has always had a black dot on one eye sack, and some dark colouring on the tail.

Ive tried to get some pictures, but they arent very clear. Its hard to get a good photo in a tank!

[mr.dark-saint]

You do know goldfish changes colors depending on water temp, right? Also, most goldfish start out brownish then turn orange-ish but they will change back and forth (to a degree) all through out their lives.

[audiman]

er, didnt know that!! LOL, does this mean that maybe the water temp is too low??

[mr.dark-saint]

What is low? I recon the tank's in the house so it couldn't be lower than 50 degrees F (unless you're cheap like me and not turn on the heater). Some also get patterns as they mature (this also get lighter or darker as well as larger or smaller). You could bring up the temp (if you want to) but I recon it'll be a little while before he goes back to the same color. I also speculate it being a seasonal thing kind a like algae bloom in indoor tanks (Spring and Fall I get the worst case on the glass).

I recall when I was a child I used to have feeder goldfish (ten for a buck kind a thing) out in a cut barrel. I used to get the black and orange which turns mostly if not completely Orange (White and Red seems to be more stable in their colorations). Then there were the Grey/Green ones that would turn pale yellow. Few times I thought the cat or someone popped them out but after a head count the numbers would indicate no one was AWOL.

[mayastarocker]

I wouldn't really worry about it until the fish starts to act weird. I am guessing by the pics that it is getting a beauty mark or something. I used to have a common goldfish and he had a black mustache right above his lip when I first put him in my 100 gal. pond. About three months later when I caught him, I think he shaved it because he didn't have it. He was about an inch or two when I put him in, he got about 4-4.5 inches about three months later. Like I said, I wouldn't worry about it.