Have you ever wanted to see fish swim around your desktop Paper Fish is not a screen saver; the paper-thin fishes swim around your active windows while you work. Make a 3D space out of your desktop and see fishes swim into the background and even peak out from around your windows. A realistic swimming motion brings the fish to life. Paper Fish is the ultimate in desktop entertainment.
Features
Two styles of fish - wrinkled paper and smooth paper
Three window overlap modes means the fish can swim where you want, either in front of your windows or beside them
Use the Inspector window to examine the 3D space created by your desktop.
Select the maximum number of fish you want to see
Select the type and size of the fishes that swim on you desktop.
Supports multi-screen systems

Link for more information: http://iamwebservices.com/products/paper_fish_mac