I obviously thought of water when I first saw this challenge.

This is actually my second try at this: the first one was the inside of a cave, but it would have ended up too dark and gloomy, and also, colorless.

The character at the far end of the tank may seem familiar, but any similarities to videogame personalities can be attributed to its extreme abstractness (haha)

(see what I did there with the composition of the blues?)