Go and find yourself a nice whitetail skull, once properly aged they make great decor, you can attach a aquatic moss to the antlers, Phoenix moss,willow moss etc.
Another idea: take a rock,boulder or driftwood and place it so couple feet or more sticks out above the waters surface, then attach terrestrial mosses, airplants,and bromeliads to the above water portions, if you make a screened above water portion you can keep things like geckos and treefrogs in the above water portion,and aquatic creatures like peaceful fish and such in the aquatic portion.