In the mid-24th century, Barbo and Quark sold defective warp drives to the Tarahongian government. Following the discovery, Barbo was betrayed by Quark to the authorities, and Barbo was left to rot behind the bars of a detention center while Quark kept all the profits.
After Barbo was released from the detention center in 2369, he told Grand Nagus Zek of Quark's treachery. In a later encounter with Quark, Zek praised him for his smart business sense. (DS9: "The Nagus")