The Amazon theme is easily among the most common aquarium themes in zoos. African Rift Lakes might be the only theme that can compete. Zoo Amazon tanks pretty much always have pacu, along with some combination of arowana/arapaima, catfish, cichlids, other large characins (Brycon, Leporinus, etc.), and stingray. Sticking to North America only, off the top of my head, Pittsburgh, Omaha, and Smithsonian all have exhibits that are nicer than Milwaukee's (better lighting and aquascaping). Many others are out there too: Toledo, Como Park, Henry Vilas, Blank Park, etc. Lots of public aquaria of course feature this theme as well, with Shedd being the standout.