Moving fry - when and how many?

[Pysgodyn]

My fry are 3 weeks old now...and I'm getting paranoid that they'll outgrow my fry tank soon.

I started off with 21 - but I've moved a few to the community tank already
I now have 16 fry in a 5UKgallon (6USgallon) tank...

How many grown guppies will I be able to house in this tank?
How long can I keep the 16 fry in there before they outgrow it?

Thanks for your help again x

 

[ScoutCarcer]

How big are they right now?

 

[afireinside]

three weeks old, they'll still be able to be in their 6 gallon tank for about, three more weeks.