So I just upgraded my grandmother's Oscar tank to a 150gal. But she wants to add some other fish with the Oscars. Is there anything I can add with them? I had heard that barb tigers would be fine but I still think the Oscars might eat them. I have also heard that red parrot fish are fine with Oscars. Any idea on what fish I can add with them or is it a definite no. They are 2 Oscars. One of then is 4 inches and the other one almost 6 inches.