Look at my Red Eye's Home and see how I planted the plants to have levels of leafs down low so they can get to the water and the cricket bowl without touching the substrate. The pics are older and the plant front right is now with four levels of leafs and is nearing the top.

Might give you some ideas on filling in more. Just don't use the arrow plant in the front left corner since the fluid from the stems is poisonous and isn't good for the frog. I'll remove it some day but they don't go anywhere near it right now.