I dont know if this has been brought up before, it seems obvious to me, but. . .
make a small white-on-black image of the pirate fish (obviously just copy the pirate fish wallpaper, but perhaps copy and paste it BEFORE opening up the wallpaper, so it will be a small image you copied), and make sure the background of your screen is black. . .
. . .(windows users) go into your control panel, under display/screensaver, use the "3d flying objects" / "settings" and "textured flag", make the texture the pirate fish image.
THEN when your screensaver kicks in, you will have the pirate fish swimming across your screen.
please forgive me if this has been brought up before, although i have been a convert from day one (ever sisnce that first pencil drawing), i havent been on the message board until now.
(OH, and you MAY need to reverse the pirate fish so it doesn't look like he/she is swimming backwards).