No CG, just water, ink, and lighting.
We used a standard 1'x2' glass fish tank, various colored inks (including some fluorescent marker fluid and milk), and some creative lighting with gels. Shot on the RED and on 35mm.
Then, inspired by the raw footage, Brian Andrews wrote a musical track. The film was then edited to match Brian's music.
Shot by Boa Simon, edited by Nate Orloff. Original music by Brian Andrews.