well I have an extremely aggresive oscar lol. And hopefully he will stop. He was doing it a little again last time I checked on him. I think he will have great coloration eventually so I would like to be able to keep him...
Do you have like a 10 gallon or something if the balas start getting beat on so maybe you can put them in there untill the oscar comms down. I think the dither fish idea is a good one. Get something thats tough but not aggressive like a catfish for the oscar to chace