I have found this video while stumble upon, It has a beautiful acquarium as “wall paper”, and the Compiz cube turned on.

Credits go to: http://www.youtube.com/user/sausagenmuff

And here is a small description of him about how to do this.

1. install linux
2. install compiz
3. enable 3d cube, wobbly windows..ect
4. set cube opacity slider BOTH to 25.
5. use a skydome and check off "animate" (panorama's from google images work well)
6. Install atlantis "fish" plugin
you can get it here:
http://gitweb.compiz-fusion.org/?p=fu...
(extract to your home dir, go into that directory inside a terminal, type "make" then "sudo make install"

Well you better see it: