I was thinking about open top with a pendant light and a bunch of plants, but it will greatly increase the cost of this project. I am converting it from a plants only terrarium. I decided to see if it would hold water (I resealed it about a decade ago), and it does. I may use a thick layer of good plant substrate and get a couple low light plants for now (along with some fish). Then later I can get a good light and complete it.