no matter how well you grind up flakes, they will still be far too big for fry of any kind,
for the best health and growth its best to hatch live brine shrimp for ANY fry,
live brine shrimp is a must for egg laying fish fry....its the only thing they will touch from my experience,
for live bearers i have had pretty good success using Hikari First Bites.....however live is always better