Clown changing colors

I bought two Ocallaris Clowns a few months ago. One is a bit larger than the other. Well over the last couple months, the larger clown has been turning black. Now he almost looks like a black clown. I was wondering if maybe I was sold Percula Clown(s) instead of Ocarillis?



Here is a pic of the clown after a few weeks in my tank.





And a more recent pic







And the other clown. This is about how the first one looked when I got him.