Since both corys and clowns like a lower ph with softer water, and because they are peaceful and rather sensitive, I'd suggest keeping them with some south American cichlids if you wanted to keep cichlids. A nice big cichlid that's peaceful is a severum.
You could also keep geos or satanoperca, something the the blue acara, a small group of SAcichlids like keyholes, and angelfish or discus even... What do you like?