Angels are not the problem, most of the time, except with each other on occasion. They surprised me as to how hardy they really are. When I got some of mine they were barely bigger than a pea. I didn't think they'd last a week. Instead they get bigger and stronger everyday. They've been growing much faster than I thought they would.
It's the other fish that you put in with them that can cause problems. I have Hi Fin Black skirt Tetras with my Angels and I have no problems between them. But with the tetras you need to make sure there is a large enough school or they get stressed and nip at each others fins. But they have always left the Angels alone.
The Danio's should be fine, but being that they are also a schooling fish, I would imagine that they need to have at least 6 in a school to feel safe.
