Do Oscar Fish Play with Toys?
Oscars will often investigate anything that takes their fancy inside the tank. My Oscars seem to take pleasure in bashing the hell out of one of the heaters. Why they do it is something I cannot answer, probably because it is not nailed down and moves around slightly. This following video shows an Oscar investigating a ping-pong ball that has been put into the tank. Oscars aren't the only fish that will investigate things that they can see floating on the surface, I have observed carp mouthing at floating objects, once they realise it isn't food, or a threat, they normally leave it alone
Fish can be trained to a certain extent to carry out simple tasks such as swimming through loops, even knocking balls into little nets. I think this is probably more enjoyable for the fish's owner, rather than the fish itself so at the end of the day have fun with your fish but don't actually kid yourself into thinking that the fish is actually having a giggle itself.