y dont angel fish babies live?

Brief：
My friends angel fish layed eggs 2 times. The first time the angel fish ate them. The second time my friend took them out of the tank and put them in .. 

My friend's angel fish layed eggs 2 times. The first time the angel fish ate them. The second time my friend took them out of the tank and put them in a different tank. They started detaching from the eggs but then they died. Why can't she keep her angel fish babies alive?

thanks

LOL although I like the sperm answer, because it is indeed needed, for any babies to spring forth. The glorious Angel Fish is a bit, well high strung (not really, just honestly has to have thing in order.) Perhaps more than any other fish, angelfish are the most difficult to generalise about. This is because they are entirely unpredictable. So I will lay a bet that it’s the water condition and or environment.

They prefer soft, acidic water, but they are successfully kept and bred in an extremely varied array of water conditions. The main thing to keep an eye on is water quality.

Set up a tank 24 in by 12 in by 15 in deep, with a mature sponge filter, and set the temperature to 82 degrees Fahrenheit. The water should be slightly soft preferably under 6GH, with a pH between 6 and 6.5. Also include in the tank some pieces of slate, and a few broad leaf plastic plants, which have had their bases, weighted down. The bottom of the aquarium is best left bare so that it can be more easily cleaned. Introduce the adults to this tank and begin feeding them with plenty of conditioning food.

Here however.is what has worked for me…In preparation for spawning, I use 6 inch clay pots that I buy from garden supply stores (never, EVER use pots that have been used previously for anything except the aquarium hobby). I used to soak them overnight in a bucket of water and then I simply set them in the 20 gallon breeder tanks with each pair. I keep sponge filters in each bare bottom tank. 20 gallons seems to give them enough room to raise the fry to an age of a week or more, without the possibility of the fry being stunted, and I feed the adults twice a day on my Discus beefheart mixture that is high in protein and vitamins to help condition them for constant spawning. The parents will pick and clean a site, making practice runs over the surface for as much as a day or two sometimes before the actual spawning begins. When the males pointed genital papilla is evident (as opposed to the females bluntly rounded ovipositor) spawning is imminent, usually within two hours.