When they first hatch, about the only thing small enough for them to eat for the first couple weeks is egg yolk. Boil an egg, and take a little of the egg yolk and squish it in a cup or bowl of water, and take an eye dropper and squirt a little bit where the babies are. After about 2 weeks, then they are big enough to eat Hikari First Bites.
As for expecting babies, all depends on the parents. Once the eggs are layed, then it takes 3-7 days to hatch. Once hatched, it takes roughly 6-8 days til they are free-swimming.