That's bad..all bad. Texas with an oscar, florida gar with an oscar in a 75g, & florida gar in a 75g.
Your tank is good for one full grown oscar & at most something the size of a convict. Florida gar's get big quick.
If it were me I would build a community around around your Oscar. This will provide a lot more movement and activity. Something like a small school of silver dollars, clown loaches, a few medium sized plecos. There are a ton of options. Just make sure whatever you add is not snack size for your Oscar and isn't going to grow into a giant or a holy terror in the long run.