First, it depend what kind of fry it's. Is it a pike, bluegill, trout, minnows, bass, perch, etc?
Otherwise, the average fries will accept normal flakes, but for top predator fish as pike or bass, I would recommand bloodworms or artemia.
edit: Sorry I didn't read well the question. I personally, feed my little yellow perchs (6 cm) once time a day or sometime every two days.