Black spots on goldfish

[arkay]

I have 2 new goldfish I got a week ago. They're bright red/orange, about 2 inches long & have fantails. One of them suddenly developed some black marks today. Is that something to be worried about?
Thanks,
arkay

 

[blueFrame101]

How young are the goldfish? Because newborn goldfish are black and as they grow up they start to lose the black colour and gain the orange. Hope this helps!

 

[arkay]

Thanks. I'm not sure how old he is. I got him a week ago & he's already grown quite a bit so presumably he's young. But he was completely red/orange originally. I was hoping someone would suggest it's a genetic quirk & since 3 days have passed since he showed the spots & he continues to look happy, I'll stop worrying.