if you are certain, of have proof of an albino being in the clutch, and there was a pastel as well, both the parents must have been carriers for the albino gene hence the albino silbling.

If you are correct about the albino being there, your pastel is either 66% or 100% het.. depending on the parents being either heterozygous or homozygous for albino..

Get what I'm saying? :p

greets,

Yaron