The problem isent size or who would over power who or anything like that, its simply water perameters and language. They don't speak the same "language" they are both aggresive fish and might be able to handle the others aggresion but they don't understand what they do to trigger the other fish. Central and south american cichlids defend there territory with aggresive displys and other signs that the africans can't read. They don't know that turning slowly to the side and flaring of the gills means get the hell away or I'm going to attack you. And oscars kept at a ph of 8 is not ideal and africans kept at 7 is not ideal. So why would we do anything but try to provide ideal conditions for our fish? Nobody is coming down on you at all just giving advice and experiance and isent that the point of the forum. I really hope you don't take offense or get upset over some constructive advise. That's not my, or from the sounds of it kings, intentions at all. We are just trying to give a heads up to what is in store in this instance. It is to be expected that fish will adventually die in a situation like this one. And nobody wants to lose fish.