They will start to color up around 3to 4 inch. But males will sometimes pull what furcifer a foai do and wait to color up till they are even over 4". The only reason I know this is that I just picked up some wild kilesa a few months back and one of the 4" + females started to get color and sure enough now its a fully colored male. Not sure if this happens alot as with all my captive raise enants they colored up by 3" and I never had one pull this hiding its color till it was over 4".