Yay! One of my two orange swords is pregnant! I hope she doesn't die like the silver one did... I let all the other fry out of the net, as they are now big enough, so she's in there now (and not looking too happy about it either)
I've got sword fry that are about 8 weeks old. The largest is just about 3/4" long. It will take about 3 months to notice the sex as the males don't start to develop their tail extensions until about that age....Also - be careful - they can start breeding at 3 months!!
How do you sell males and females before they're sexed???? I've seen swordtails who have just begun to develop their swords in tanks to be sold.....That would make them in the 3-4 month old range. So it's not necessarily too young for them to be sold. As long as the males begin to show their coloration and sword they can be sold.