Aggressive and expansionist, the Etanians annexed the colony planets of other species by staging a "natural disaster", then claiming the planet once the population had been evacuated. In 2373, they sent numerous artificial asteroids to bombard a Nezu colony.
The manufactured nature of the asteroids was discovered by the USS Voyager crew, who were assisting the Nezu with the emergency. Voyager subsequently defeated an approaching Etanian starship, using tactical data collected by the Nezu Doctor Vatm. (VOY: "Rise")