It is highly advisable to leave the fry with the parents for about 2 weeks or so then the fry can be removed to another tank if you want, for grow out. Make sure this tank has exactly the same water parameters as the main tank. They can also be left in with the parents for as long as they will allow, providing the parents don't get too stressed or have chunks eaten into their skin. Discus fry have little teeth, when feeding they can chew into the skin by eating through the mucus as they get bigger. After about two weeks you could add newly hatched brine shrimp to start weening them off their parents.