I have a tank that is 75 gallons with a Jack Dempsey, An Oscar, and a Florida Gar. I'd try to stick with fish around the size of the Oscar. I also agree the Chanel Cat would be a bit big. I would suggest a fish that could definitely compete with the Oscar and Jack for food. My Gar tends to just lay on the bottom and wait for food, while the Oscar and Jack are all over it.
how would smaller pbass like kelberi work, or do they get to big? also, if an arowana and pbass end up not working, is there anything else besides aggresive cichlids i could get cause i dont really want my fish killing each other.
You would have to stick with the kels if you want more than just bass in the tank and pretty much any cat fish that pairs well with bass are gonna be too big for a 240 plus ocells arnt a peacefull bass lol there not that bad but there my number 2 aggressors in my tank right now next to my bigger zulies me personally I'd put 2 bass and a few dats in there that are bigger than the bass or if you can do rays I'd go with a ray as well but they can get expensive
Kelberi should work I've never seen one bigger than 18". I've heard of them getting bigger, but, rarely do they get bigger than that. Maybe get 2 a school of silver dollars and some dats ( they grow slow but will also get very large )
If you want a cool, big cat, Lima Shovelnose is the way to go. Any other monster will outgrow that 2' width. You could also include other large SA cichlids, just stay away from the more aggressive ones such as jaguar and dovii, as they will bully the oscar to no end. Another option could be some bichirs. Shouldn't have any issue with them and they are much more interesting than big cats to me.