Hi Fishyy
Well, in my limited experience, the black marking start to show through first, maybe after about 10 days or so. A week or so later they will begin to show up some yellow markings. Mine are about 5 weeks old and they are still limited to black and yellow shades, but I think that other shades will start showing through in the next couple of weeks.
Guppy fry do develop more quickly at higher temperatures. My tank is just at 25 degrees centigrade, but I imagine that if I kept it higher, the colours would have come in sooner (I think).
My week old fry are about a cm or so, but again this will depend on the water temperature.
HTH Kathryn
