When I have needed to mount pots in the upper part of a viv like on the sides or where there is no background I take a plastic pot and cut it inhalf so it fits flush on the glass wall. Then I gorrilla glue it or epoxy it to the sides and hold it in place with tape until it sets, This manke a great option as they have drainage and if not a few small holes drilled in the bottom work fine. Then I cover the plastic pot in gorrilla glue and cover it in eco earth so it looks like a natural part of the viv.

There are many other plants to consider. Pothos is just one. You can go with bromeliads, hoya's, dischidia, philo's, anthuriums and others. And Milk's are readily availible in a few places at decent prices. I can help you out there if you need it.

Michael