Water creature/Aqua
Aqua creatures are kept in big aquarium, separated.

Fire creatures/Ignis
Ignis creatures are being kept in a special, heat resistent sector. They have separated cells and heat resistent decorations. 

Air creatures/Aeris
Aeris creatures are kept in a high ceilinged sector. There are a lot of tree decorations and hiding places behind the glass of their display.

Earth creatures/Terra
Terra creatures are kept in a forest-like display. There are a lot of trees and plants.