How long has the tank been set up? I'm assuming it's cycled and stable, yes?
You could probably do something for the bottom, depending on your substrate. If you have sand or round (not sharp) gravel you could try some Corys, a group of 6 would do nicely. You could probably also add a shoal of smaller fish like neon tetra, maybe 6. Just keep in mind if your livebearers breed (assuming you have mixed sexes) your tank could become overstocked pretty fast.
Welcome to AA by the way!