Help with Dendrobium aggregatum

[d-prime]

Hello everyone,

I am having difficulty with my Dendrobium aggregatum. It was my first orchid that I had purchased 3-4 years ago for a terrarium. At first, everything seemed well until it began losing its roots. Right now, 5 pseudobulbs remain, three of which have healthy looking leaves on them. The plant has no root system, which concerns me. I have it mounted on tree fern inside a vivarium, approximately 8 inches below a 6700 K, 9 watt coralife fixture. I would really appreciate help with this plant, as it is by far my favorite.

Daniel