Predatory Fish for Amazon/South American Themed tank?

[Fanatic_Fish_Lunatic]

Can you guys give me some recommendations for predatory fish from SA/Amazon? The tank is 800 gallons in total, currently have an oscar, a monoculus peacock bass and a silver arowana in the tank.

 

[danotaylor]

What are the tank dimensions? LxWxH?

 

[A201]

Look at the Festae & the Rivulatus.