suggestions?

[pandorasBox]

i would really like to build an ecosystem out of a 4x2x2 aquarium i have. i have already thought about the design that will have a pool, fountain with a filtration device, and large limbs for the arboreal animals. however i am unsure what i can exactly house together? i have seen pics of arboreal geckos housed with certain types of frogs. so my question is what would be the best diversifyed selection of hearty animals that could all be housed in the same enviroment. any thoughts or suggestions would be great for i have found nothing on the net. i should mention this will only be for display. i have no intentions on breeding or really handling this animals. thanks.