The Ubeans were a species native to the Delta Quadrant.
When Neelix and Wixiban were partners in trade, they had a run-in with the Ubeans, and Wixiban was forced to serve a year in an Ubean prison. According to him, conditions there were harsh, with unimaginable punishments, vermin that chewed on inmates, and having to eat worms to sustain himself. (VOY: "Fair Trade")
This species was only mentioned in dialogue.