Do you mean hemianthus callitrichoides (dwarf baby tears)? They look quite cute... I think I saw them at petsmart as well and considered looking the plant up. I do have two anubias barteri var. nana plants that seem to be doing ok so far. One is mostly submerged and the roots are woven through the bit of malaysian driftwood I have that sits partially under the waterfall. It has a few leaves above the water and no wilting or discoloration (yet). The other one is completely submerged, but also attached to the wood and they are both partially shaded from direct light.

Turns out the light was cheaper through the website with free shipping so I went ahead and ordered it. This viv sits on my desk, which has a book shelf that runs across the top of it. I plan on mounting the clip under that bookshelf and hanging the light upside down. I can even mount it on the right wall of the second bookshelf if need be (the desk is caged in with a bookshelf on either side, as well as above). I wanted the viv here so that I could watch it while I worked on my laptop. The little waterfall sound is so soothing.