actually the egg you can just let it be...the parent will take care of the fly,y they will eat the egg bcoz they was disturb,you should cover your tank with some newpaper and try not to disturb them.but is ok to raise the fly without the parent,coz angel is not like discus.the fly wont really eat the thing from the parent.after about a week,u will see the fry is free swimming.then u can try to get them some live plegton "sui ji",over pudu u can get a bag full of it for one dollar.another way is feed the dry egg yolk....but this will clouded the water and the result is not so good .some fly will just not take it and die.i find the "sui ji" is the best,you can keep 80%-90% for my experince if they have good quality food and water condition.but if u feed egg yolk ,mayb40-50% u will get.it take about 3-4 months for the fish grow up to a 20 cent coin size.and they will come in different size if they have not enuff food.all angel is very easy to breed,u can try to cross gen also.using marble with koi will come out some nice fish.i tried using blue blushing and albino,the result also very good,i got few red eyes bulshing last time.hope this information will help.