I prefer to separate them at wiggler stage, before they are free swimming.
I have also successfully raised them with parents. I have also siphoned them off at free swimming stage as well.
To prep to strip the fry, I like to give the parents a cave of some sort to move the fry into (you'll see in my photos, that I have caves and ceramic logs). In the evening, as they prepare for sleep, the parents will move the fry into the cave. Then you can take a net to keep the mom from going into the cave, then take out the cave and put into a different aquarium (or, as you see in my pics, I pour them into a clear dixie cup). I like to raise them in 10-20 gallon tanks.