Well, even if they weren't aggressive towards each other, I'd imagine an african cichlid and South American cichlids would have in-compatible water chemistry.
Also, the aggression would probably depend on the size of tank you have, and the type of decor you have.
Other than that, I don't know if I could help you further due to my limited knowledge of Parrot Cichlids. Hope this helps!
-TDG
It would be a 55 gallon tank.
And correction, he has 3 Jack Dempseys, not 2. oops.
Both of his oscars (one black and orange, one albino) are 9-10 inches long.
2 of his Jack Dempseys are about 4 inches long; One of them is 5-6 inches long.
His convict is about 3-4 inches long.
He's willing to sell his 55 gallon tank to me, with a stand, including the fish, along with the gravel, filters, heater, and decor for 175 because he wants it gone. It's a great deal!
I've seen pictures of all the fish, the tank, and the stand, but I'm going to check it out this weekend.
I'm a sucker for Jack Dempseys and Convicts (even though I prefer South American New World Cichlids)
but I really don't want them to kill off my parrot fish.
If I only decide to take the Albino Oscar (my favorite), 2 of the Jack Dempseys, and the convict, would it be possible to add certain South American cichlids to the tank later? Such as rams and some other New world Dwarf cichlids?
I've looked up online the water paramters for both oscars and parrots, and they overlap together, so I don't see why they wouldn't be able to live in the same tank if there end up not being any aggression issues.