If it was just the female you had in the trap, then the eggs would not have been fertilised and never hatch. When egg layers spawn, the male fertilises the eggs as the female lays them.
Outside of a proper spawning tank, very few eggs will avoid being eaten. In a breeding setup, the hatching percentage tends to depend upon the water chemistry and the quality of the breeders.
Good quality parent fish laying into water of the right pH and hardness will have almost all of the eggs that get fertilised hatch, (external fertilisation is a bit hit or miss). With characins, normally the harder the water, the lower the percentage hatch. The eggs develop, but the Calcium in the water reacts with the egg shells making then to tough for the fry to break out.
Once hatched, the fry will feed of their yolk sack for a period, that time varies with species and temperature. Typically several days to a week. When free swimming, they need feeding with as much food as you can get them to eat at frequent intervals during the day, not just once or twice a day - BUT - all that food and the waste produced can turn the water quality bad very quickly. This cannot be allowed to happen, you must keep your water quality very high to raise a good numbr of fry.
If you can't culture infusoria, the better quality liquid fry foods are pretty good now. It is, however, worth learning to hatch brine shrimps, although you should be careful about how you serve them - you do not want to get salt in the breeding tank.