Maybe some colors get their colors faster? Don't know. I've never seen much color before about 1/2 inch with guppies. At least some platys are born with color, though it darkens as they grow up.
I currently have about 40 guppy fry, 8 days old, as well as about 20 platy fry that are 8 days old and another 20 or so that are 2 days old. The guppies are all kinda silver gray so far, but a few are beginning to show darker areas on their tails. Their mom is silver gray in front, back half of her body and her tail are dark blue, tail has silvery opalescent spots. Dad could be red/black tux or one of three turquoise/blue tux males, with varying shades of blue, so it will be interesting to see what I end up with.
The older platy fry were born to a sunset platy mom, and although they are only about ____ that long, they are bright yellow. They were when they were born. They may develop mickey mouse spots and/or get darker orange to red as they get older, because their dad could be either a bright orange sunburst platy or a red mickey mouse platy.
The younger platy fry, born Sunday, are still really tiny - about ___ that long, but are already showing darker scales on their sides. Since their mom was a red mickey mouse platy, their dad must have been my neon black painted male, who is orange where he isn't metallic (or neon) black, so I suppose they'll end up like that. Maybe darker orange/red, since their mom is.