angels like many fish normally need a few batches of eggs before they get the idea of parenthood. i was quite lucky and mine got the hang of it pretty quick on about the 3rd time.
breeding fish in a com tank is not the way to do it im affraid because as much as the parents can defend their eggs there will always be some fish that get through their barrier, especially at night. if the parents feel too threatened then they may eat the eggs themselves which is another reason to breed in a seperate tank. angels are excellent parents as are most cichlids but in a com tank they dont really stand much chance of many eggs/fry surviving im affraid. if they dont get eaten they will end up in the filter.....
a breeding tank doesnt have to be massive, just big enough for the fish to feel comfortable. they also have very little decor and usually just a breeding slate or cone etc for the eggs to be laid on so are not the most easy on the eye but then they are not for that reason. some people leave the parents to it to learn as they go which can take a few attempts and some people remove the eggs and raise them using a spare tank and an airstone to aggetate the water near the eggs which simulates what the parents would do using their fins and fanning the eggs. this keeps water flowing over the eggs and helps to prevent any fungus appearing. eggs that turn white are infertile eggs and the parents will usually recognise this and eat them but if the parents and eggs are seperated the infertile eggs are best removed by the owner but be carefull not to damage any good eggs. some people will add meth blue to a tank of eggs which again can help prevent any fungus growing on the eggs.
the eggs will become wrigglers within a few days and they will be stuck to the object the eggs were laid on by their heads. once free swimming the fry will feed from the yolk sack for a couple of days but then its all down to you to feed them and the more times a day the better. one thing to remember is that they wont eat much at eat feed due to the tiny size so be carefull not to overfeed. a panda cory is a great adition to a fry tank to clean up any uneaten food and wont eat the fry. dont rely on the cory to keep it perfect though as this just wont happen which is why plenty of water changes will be needed to keep the water parameters perfect for the new fry and to promote good growth and health. use water from the parents tank to do the water changes so the fry are getting exactly the same water all the time, this also keeps the parents in good health as their water will need topping up constantly. fry are very sensitive to poor water quality and will die if not cared for correctly.
once the fry start to grow and become more angelfish like they will require more space. this is the part that can make an angel a stunning example or a stunted fish. as they grow they need more room to do so and they will need to be split up into groups. this is where many tanks are needed as you can have a huge amount of juvi fish to care for. as they keep growing they will need to be split up again and so on until they are all in tanks that can accomodate them until they reach a size that can be sold on or added to your tank or taken to the lfs. the bigger they are usually the higher price you will get for them. once they are big enough they can be put into a very large tank to live together again as a group as by this time your whole process will probably have started again with more eggs/fry that will need room in the grow out tanks.......
its a very time consuming side to the hobby to get involved in and if done correctly will need plenty of room for tanks etc etc. also each tank will need heating, lighting, filtering, feeding and fresh water which can be costly to set up as well as run. it is great to raise fish and to see them grow up but think about how much per fish you will get when big enough to sell and do the maths on the set up and maintenance to see if its worth it. small angels sell for about £3 and adults depending on strain about the £10-15 mark in an lfs so you will get probaly a third of these prices from the lfs
i hope ive not put you off as this wasnt my intention but its not like having livebearers in a tank breeding like mad, its a totally different experience thats hard at times and very time consuming and dedication is the key.
i also hope ive answered your questions as i have got a but carried away and waffled quite a bit and probably covered more than you asked.....
good luck with them