Initially, the fry need access to rotifers at a defined concentration so they don't starve. That concentration is nearly impossible in a display tank setting. There are 2 approaches - remove the eggs and hatch them in your fry tank or catch the fry and transfer them to your fry tank. After metamorphosis, you can move them to a grow out tank. All of this requires monitoring of ammonia, the correct density of the right food at the right size, constant temperature, correct light intensity for the correct number of hours, and the list goes on. All of this makes it nearly impossible for fry to survive in a display tank - not to mention fry are a delicious snack for any other livestock in the tank.