Here's two of my orandas (Paisley and Penelope)
Paisley when I first bought her:
Penelope about two months after I got her (she had black on her wen and it was way thicker in other places when I bought her:
Today, Penelope is 100% orange, and Paisley has no black either.
SO, don't fall for those adorable black patterns cause they tend to disappear.

The whole "panda" colouration that some stores market doesn't last (unless you are buying high quality show fish that have good pedigrees).