Hi. Since the tank doesn't have a planted tank type substrate and pretty low lighting(?) I would stick with some hardy plants like java ferns, anubias, bolbitis. If you really want a grass look go with dwarf sag. There are a few different kinds of ferns, I like the 'windelov' and needle leaf varieties. Another thing to consider doing is putting something like amazon swords in directly underneath those LED's, they may or may not do well, but i think its worth a shot. Since you have sand I would go with a decorative terra cotta pot (no glaze/paint) to plant them in. That would make maintenance easy if you ever wanted to move them around, plus they'd benefit from having nutrients in the pot that wouldn't be available in the sand.