I agree with beau. For some reason polys are just ignored. Only fish i ever had that had issues with polys that i can remember were vieja argentea, but he also hated everything.I'm afraid my oscar is too big and cranky to introduce a new fish into his life.
Lie beau said just make sure its a good sized poly. What else is in the tank ? The only problem i see is feedings. Cichlids can easily out compete polys for food.Do you think it would be better to just drop a poly in his tank? . . . or I could put them in tanks side-by-side for a while so they could watch each other.
I've done this with other fish and had some success.