varies from fish to fish...some can try to eat them from the time they are the size of a dime, some never touch them...rule of thumb is to generally not keep angels with anything that will fit in it's mouth when it is larger
are they peaceful enough to be in a community tank?
I have 4 angels with my lutino neons and yes they do try to eat the neons; however the tank is 62 gallon and heavily planted allowing for great escapes by the neons. Touch wood I've not lost a neon to an angel yet.
You may take that as you wish, whether it is safe or not for you to have angels and neons together.
I have 4 angels and 6 neons and there isnt any conflict not even fin nipping as i have seen yet.
This subject comes up all the time, and even tho the technical answer is no, many people have succsessfuly kept angels and tetras together and many have failed; it all depends on the situation and bit of luck.
Your NOT supposed to rob banks, but people have and people have got away with it. But people have been caught too.
Angel is a predetor.
Neon is a prey.
When prey is kept with predetor, even if predetor is too small to eat prey, stress levels rise.
The larger the angels get, to more stressed the neons will become.
The stress of the neons may result in disease in the tank before the Angel is big enough to eat them. Maybe not. With so many appropriate fish out there I don't see the point of the risk, but to each his own.