IMO in a large enough tank you could have angels with things such as firemouths and convicts. in a smaller tank this would maybe not be so clever. the larger the tank, the more you can get away with. ive got a 6 foot tank with discus, gold severums, uarus, a huge featherfin syno and a large pair of kribs, angels etc. all these fish are pretty much "forbidden" with discus. the bottom line is, if you had a big enough tank you can have a broader spectrum of fish in it, as they have more space to themselves. if i had say a 10 foot tank im pretty sure i could accomodate some dwarve cichlids amongst large things like uarus and severums providing the right decor was in the tank.