Aquarius is the debut studio album by English progressive metal band Haken. Despite the band having released two previous demos, none of the multiple songs already recorded were re-released on this album. A 22-minute medley of the whole album, except for the song "Sun", was included in their live album L-1VE.

Aquarius was largely written on the piano by guitarist/keyboardist Richard Henshall and then developed with contributions from the rest of the band. Its track lengths are typical of progressive rock and progressive metal, with the shortest track being just under 7 minutes and the longest being nearly 17. It is a concept album about a mermaid, discovered by a fisherman and sold to a circus, whose blood is the only thing capable of saving the human race from a flood resulting from global warming issues. She ultimately dies for mankind's sake.

The album artwork was created by Dennis Sibeijn, who has also worked with 3, Job for a Cowboy, and See You Next Tuesday, among others.