I have noticed subtle color change in some of my hatchlings in as little as six weeks. some are a little bit faster to mature and some aren't. color also can change based on the animal's "mood", there have been times when I thought my geckos color or pattern was changing one day and the next it was back to normal. sometimes you just have to wait and see. you can probably make a fairly accurate assumption of color based on the parents however.
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2.2.5 Crested Geckos
2 ringneck snakes
0.1 packman frog
1.1.1 Box Turtles
1 Redclaw Scorpion