Guppy fry already showing color?

[YoungGuppy]

They are a week and a day old. I have 9, about 3-4 are showing black on their tails and a couple have black on all fins. I thought they weren't suppose to show color for another couple weeks? And are these most likely males?

They are in their own 5gal, temp is a steady 80. Filter is on the lowest setting. And I feed them goldfish flakes 1-2 times a day.

 

[Robynleigh]

I have a couple that show colour early too, most of the time they are male, but it's too hard for me to be accurate there - someone with more knowledge might be able to tell you more,

Also have you thought about feeding them some more variety, not that they can't live on flake but variety is good and helps growth.

My babies get egg yolk every 2 days, bbs every day they don't get egg, then some finely crushed flake and occasionally I'll mash some shelled peas and give them that too. I am also going to try bloodworms on mine in the next week or so. I also give them 4-5 small feeds a day - I read they empty their stomachs every 20mins or so, so plenty of small feeds throughout the day helps (if you can) - I have about 20-30 babies at various stages of growth at the moment.