I took my family to the Tropical discovery exhibit at the Denver Zoo and was surprised to see a better tropical fish display than at the local aquarium. My faves are the true parrot(The green one) and 5' aropaima
The whole building is a greenhouse and it looks like most of the plants actually grow out of the tanks so those are the roots you see in some of the pics. it's really cool, I love the way they made it like a small ecosystem.Also the pacu (if you're into those) is the biggest I've seen. If you live near Denver I highly recommend stopping by to check it out!