4 month old guppies not gaining color

[ThePurple12]

Usually a freshwater fish, but I have a guppy question. I have 9 four month old guppies and they're all tan except for one, which is grey with a little bit of black. They don't have a single drop of color on them. I've been feeding flake and pellet twice a day. Any ideas?

 

[ThePurple12]

The mother was a normal fancy guppy, not sure about the father.

 

[ThePurple12]

bump, any freshwater people?

 

[nereefpat]

Are they simply females?

 

[ThePurple12]

I guess it's possible, but pretty unlikely for all 9 of them to be females. Also, females should have at least some color...

 

[WVNed]

Mine show color when about half grown.
Original pair

Offspring

Even the small ones quickly have some color on their tails.