How Old Do Swordtail Fry Have To Be Before You Can Sell Them/Give Them Away?

Now would be fine, as soon as the baby's are out, they are totally on there own and do not need there parents for any reason. In fact, if you leave them with there parents, the parents will eat them. However, fry are very fragile so unless your friends tank is a fully cycled tank that has been established for a while, the fry will likely not make it long. Just make sure your friend's tank is fully cycled and the water quality is good, also make sure you bag the fish and then float them just like you would if you bought them from a store :-) Hope this helps!