It really depends on many things..
1)how well your female is conditioned
2)how many eggs get fertilized correctly
3)possible fungus attack
4)possibly no survivers if dads an egg eater
I could go on and on...
I've read that statistics say that you'll end up with half of the fry you start with and that they stop dying off at a month old. In my personal experience I've had a couple of spawns without one single loss from the time they hatched.
Long answer,I know I'll guesstimate and say on the average....45ish (but possibly less but almost certainly waaay more )
As Wuv said, it varies...basically there can be 50-1000 eggs, of which all or none may hatch, of which all or none will survive to adulthood, Lol. I would say the average clutch of eggs is 100-400 with the same number for hatchlings, and survival rate has everything to do with how well you raise them, good breeders can have near 100% survival if everything goes perfect.