Google for more info,lots out there.
Free swimming is right after the small fry use up their yac sacks.
The major of the web sites list 5-7days.
I find it takes a few days more before the fry really get the hang of swimming.You will know.They go from a brown wiggling mass under mom.
Then they start spreading out (looking for food most likey)
When they spread is a good time to start feeding.
Very Very small amounts on Baby brine shrimp or finely powdered good quality flake blown gently over the group of fry.(turkey baster)
Little goes long way.
I have to laugh here cause :
You will be bitten by the male and chased away.
They will bite the Baster(or what ever you use)
Very protective !
Good Luck