Hybrid Powder Blue with black fins?

[GARY666772]

I was curious if anyone know anything about powder blue hybrids? I have seen photos of them with black fins and I have seen them with all yellow. Most I see are yellow. Is the black just a rare thing or is it something that comes with maturity of the fish?

 

[GARY666772]

Black fin

 

[GARY666772]

Yellow fin

 

[DasCamel]

Mine was yellow and stayed that way for almost three years. Black is an interesting variation.