A 29gal is pushing it. Angels like there space and if the rams breed then there might be trouble. I keep them together in my 55G but with no problems since it is a big tank.
Jeez from your signature it looks like you have a crowded space. I really would not put anything else in there with that many fish. You might actually be able to do it but why its cruel*thumbsups
If all you have in the 29G is 2 Rams and an Angel then yes it could be done. But 1) That would make for an awefully boring tank and 2) You have other fish in your tank currently so NO it cant be done.
I dont think that 3 angels by themselves should be put into a 29. Your tank sounds very crowded. Plus, nippy serpeas tetras shouldnt be put with angel fish, it will stress them out very much.
