But their numbers also begin to diminish. Perhaps the reason angels can lay eggs every two weeks and the eggs generally number 300 or more is the mortality rate is so high at this stage. From the eggs that were laid, there are only a few dozen still swimming. These will be the fittest and most likely to survive.
I've heard from professional breeders that the parents will eat the smallest and weakest of the fry to give those who are larger or fitter a better chance at survival. Some breeders allow this natural culling process. Others will remove the parents immediately after the eggs have been fertilized so they can attempt to grow all the angels to maturity -- or at least to the stage where they can sell them.
The smallest angels are sold when their bodies are the size of a dime. It's better if they are the size of a nickle or larger, as this gives them the best chance of survival in their new home.