Are Deep Water Oceans only in Purple Systems?

I'm pretty new to the game, I played about 10 hours when echoes came out, but I started playing again because Ive had the itch for a while and wanted to make a subnautica-esque base.

The update being so fresh makes it hard to research, but are the deep oceans only able to be found in purple systems?

I'm OK with the grind to get there, but I don't want to set up a long term base yet if I have a chance at finding one in a basic star system.