The Selsseress were an amphibious species native to the planet H'atoria in the Beta Quadrant. Barely sentient, they could only thrive in places of high humidity, so they mostly lived near the planet's oceans.
In early 2381, H'atoria was devastated by the Borg, completely devastating the Klingon colony, and leaving only a few surviving Selsseress. Later that year, the world was conquered by the Kinshaya. (ST novel: A Singular Destiny)