Bit like us really, they will stay there for as long as they can. I wouldn't worry Alga, they will be fine. You will probably find that they venture out at night, then go back in during the day. You will also probably find that half of them are already scattered about the tank, hidden under various rocks etc.
The male will continue to tend to his new batch, and ignore the old fry.
Well done!!
Don't forget to update the register!!
rob