Pisces Base
From Wookieepedia, the Star Wars wiki.
Pisces Base was the name of a provincial floating city located on the ocean surfaces of Dac. It subsisted on fishing, tourism and underwater mining operations. In 5 ABY, Admiral Ackbar brought Luke Skywalker and the droids, C-3PO and R2-D2 to Pisces Base aboard a modified QH-7 cruiser. From there, they acquired a Calamarian minisub and traveled to the undersea city known as Aquarius.
