AQUANS

Planet of Origin: Argo,  a seismically-unstable planet. Once a land planet, but its surface became almost completely covered by water, following a series of violent seismic disturbances, leaving only a single large landmass, with a few associated outcroppings.

The Aquan are an humanoid species which developed an advanced planetbound civilisation. They are good example of forced evolution as originally air-breathers were they mutated themselves to become able to breath underwater after massive planet-wide earthquakes flooded the entire planet.

They are governed by the Ruling tribunal of the Anquans and follow the Aquan Ordainment, an ancient set of rules.

Source: Star Trek Universe,  (TAS: "The Ambergris Element")