I have kept fish with Oscar. In the past I bought him feeder fish that got too big for him - or so I thought. We had them for about a year together than one night Oscar went nuts and attacked them all. He took a side flipper fin off of one. Poor guy couldn't swim right for some time. The fish that were okay I gave to a
pet store. The others I nursed back to health and gave to the pet store. Even the one that had his flipper nipped off made it and learned how to swim again. The people I asked for help (way before I found this site) said to flush them. I just couldn't do that.
Now Oscar just has fish with him in the summer in the pond. I think the pond is big enough and Oscar is lazy enough. I also am sure to keep Oscar well fed in the summer. Also full grown Florida red bellies are not supposed to eat fish. Only the babies. Not saying he may not get a craving for them.