This is a port of the Asciiquarium program to a KDE screensaver. You can configure the number of fishies and not much else right now. But it's pretty cool all the same.
The port to KDE 3 was done by Maksim Orlovich and myself. I then ported it to KDE 4. Since it is a KDE 4 program it requires the normal KDE 4 development chain including CMake to compile it. If packages are created you can let me know and I'll link to them if they are small enough.
Note: This screensaver is included in the KDE Software Compilation since version 4.2, in the KDE Artwork module.
There's a KDE 3 version available at kde-look.