well mostly if your tank is big enough u dunt actually need to take the attempt the seperate the fry from their mom .Make sure ur tank is partially planted with weed or floating weeds so that the fry can dodge their parent by hiding within them.since u already put them in a box, well u should let ur fry to stay there until at least they are a month and at that time they can feed on other food too lie the brine shrimp. well i just tell this by my experience. hope it help..