Amazon themed tank . . . large fish?

[purplestarfish]

Since I'm doing a pretty large tank redecoration etc, I was thinking about focusing on fish that are primarily based in the Amazon basin (ie, neon tetras, Bolivian Rams, cory cats, etc.). However, all the larger fish that are there aren't what I'm looking for. For example, discus fish do better in species tank, something I can't do already because I have a few cyprinids and loaches I can't bear to part with (despite the South American idea formulating; like I said, I'd be focusing on them but not only displaying them!). Also, Angelfish frequently end up eating small fish (like neon tetras) and they often become increasingly territorial. That doesn't help either. So are there any rather large fish that don't have these problems? Thanks in advance . . . Oh, as an afterthought, are arowanas South American? Just occured to me that they may be . . . but there's likely to be an issue with them too, like the size they'd reach. In any case, I'd still be fascinated in knowing more about the larger fish of the Amazon; thanks!

 

[Xenos]

As I understand it, Discus only need a species specific tank if you intend to breed. They will either refuse to breed or eat their young. My Uncle has had Discus for his whole life almost and he has a nine year old discus that he has housed with rummy noses or rams and angels. He says they will school with any non-aggressive fish. He also says you ought to be in to the hobby deep because they require frequent water changes (Daily) and they live a long time. He has a bunch of other discus but the nine year old is the only one I remember when I see him.