Fourth Universe

The fourth universe was the location of the planet Quinnis. (TV: "The Edge of Destruction", AUDIO: Quinnis))

As it did not run parallel with the primary universe, its time tracks crossed each other. The First Doctor told his granddaughter Susan Foreman that it was the furthest that they had travelled since leaving their home planet. (AUDIO: Quinnis)

The Blitzen fish were native to the Aurora Gloriousia in the fourth universe. (AUDIO: Relative Dimensions)

By other accounts, Quinnis was instead located in the Fourth Galaxy (PROSE: The Edge of Destruction) or Galaxy 4. (PROSE: The Devil Goblins from Neptune)