Always add Prime to tap water! or a similar dechlorinator every WC!! Just to repeat, daily WCs. The fry will not eat until the egg sac is gone so any food before that is just polluting the tank. Very small amounts of food each time, maybe just a small bit of wafer. See what & how much they eat.
This is just your practice round...observe & learn. But don't be too distressed if it doesn't quite work well the first try. Later hatches may well be larger & you'll need to up your game.