a 21" high resolution screen running Djohn's version of this screensaver in my office, and I can confirm that it's astonishingly realistic. I was not in favour at first, but was talked into it by a (female) colleague, and now I'm hooked (ouch!).
"The 3 fish demo in the XP Plus! Pack and our full 7 fish version are two separate programs. Jim Sachs, the creator of the Marine Aquarium screen saver is not affiliated with Microsoft and does not receive a dime from sales of the XP Plus! Pack. Some time ago, Microsoft spotted our Marine Aquarium and was so impressed at the way the program utilizes Microsoft's Direct 3D technology they contacted Jim who agreed to create a 3 fish version as a show piece for the XP Plus! Pack. In return, Jim's product is exposed to millions of XP users who can purchase the full Deluxe Marine Aquarium if they are so inclined."