A new port of Aquaria has been completed by the prolific Linux codemaster Ryan C. Gordon.
You can download it here and play it until January 13th: aquaria-beta-installer.run
The installer has beta test details (bug tracker, discussion list) in its README.
Thanks in advance for your help and a huuuge thank you to Ryan!
P.S. The Aquaria: OST is now available digitally!