The Yalosians were a spacefaring civilization. They breathed a corrosive mixture of 60% nitrogen, 10% benzene, and 30% hydrogen fluoride. Such a mixture dissolves carpets. They also could not perceive the red-orange part of the Human visual spectrum.
Deep Space 9 hosted the Yalosian ambassador in 2371. Major Kira Nerys was in charge of preparing the quarters for the ambassador. (DS9: "Improbable Cause")