I was watching this octopus video yesterday- you might have already seen it- and when I got annoyed by the incessant yammering of the spectators in the video, I muted it and popped on the first aquatic-themed music I came across in my library. The results were extremely enjoyable, even majestic, from my point of view. Mute this video, go fullscreen, and play this track.
(The track is "Bora Bora" by Piero Piccioni, from the album Bora Bora. Get it here.)