Here are some images of a hexagonal terrarium. These are 22″ high.

Screen terrarium

Here are some images of a tall screen terrarium. The sides and front panels are lined with plastic; the top is lined with mosquito netting. These are 36″ high.

Although the bottom tray is only about 2″ deep, I found a small 48 GPH pump that can work with very shallow water.

This short clip just barely shows the moving water feature — that’s within a plastic tray that’s about 2″ deep, but there’s still about 1″ between the water surface and the top of the tray — no danger of overflow unless someone adds way too much water (or messes with the hose or something).