Kandalinga

Kandalinga was the home planet of the Fishmen.

Astronomical Data
Kandalinga orbited two stars. One was small, very bright and closer to Kandalinga. The other other was larger and was less visible from the planet. Kandalinga had no dry land and was covered in oceans, though some areas were shallower than other. There was a wide variety of native fish, including some which were larger than the TARDIS. (DWA: The Fishmen of Kandalinga)

History
Kandalinga was originally inhabited by the Fishmen, but the Voord later took over the planet and enslaved the Fishmen. They tried to create land, using the Fishmen as workers. The Doctor later arrived and landed on one of the only structures built above the tops of the waves. He was able to stop the Voord, allowing the Fishmen to take back their planet. (DWA: The Fishmen of Kandalinga)