If it is a zoo, then they should know what they are doing. I have been to many pet stores where they keep Litoria Caerulea (Whites Tree Frog) in a semi-aquatic tank with it half full of water, and it makes me sick. I have my White's Tree frog in an arboreal tank with branches and leaves and a substrate of eco earth with a shallow water dish. I would say that as long as they have land to perch on, that they should be fine.