Guppy fry gender?

[bimmerboy]

This is in regards to the 1 guppy fry that I got as a bonus fish. After being removed from the tank for a week, she has stopped nipping on others tails.

But now, what I first thought was a "she" may actually be a "he". Do guppy fry go through "puberty" and develop a gonopodium? Or is she just tucking her anal fin up so that it looks like one?

 

[The-Wolf]

I'm not a guppy keeper but I have been told that they can change sex.
I if thats true but that maybe the answer.

 

[Stryker]

My guppy fry looked rather different when they were just 2-3 weeks old. First of all the females will be rather bigger than the males, then a few more weeks after that the male colouring appears.

 

[fishrock]

i beleive the time frame is one to 4 weeks the male gonopdium develops.