We first shared that Aquaria was being ported to Linux back in August and then Ryan confirmed he was working on it, and now its close to completion. Ryan Gordon is hoping the Linux client will be fully set by mid-January. The native Linux version of Aquaria can be downloaded from right here with no need to mess around with any registration steps or other processes. The announcement was made at Icculus.org.
Bit Blot's Aquaria is an underwater fantasy game. More details are available from the game's web-site.