Pardon my ignorance here, but most (or all?) of those plants are fake, no?
What makes this a vivarium? And do people frequently keep balls in vivariums?
I ask because I like building complex, bioreactive setups with running water and plants and lighting and whatnot, but I've never considered trying to keep a ball in one. Just turtles n' frogs n' watersnakes so far.
Sorry to derail, just got me thinking.