VR Aquarium
This aquarium screensaver is probably the most unusual screensaver I have seen. I would describe it more as a game than a screensaver. It allows you to completely build your tank from scratch, buy and sell fish, and learn about all the fish species available.
In fact, this piece of software makes an excellent learning tool for anyone interested in learning more about fish in an interesting way. If you are looking for a screensaver for your kid(s) then this is the one to consider. The animations are a little funky and "cutesy", but this screensaver is not about being realistic. It is about being fun.
What makes it truly "VR" is the fact that your fish grow and that you can breed them. You can go to the fish shop and buy young fish, go to your tank and breed them, then go back to the store and sell them! Brilliant!
It's a few more dollars than most 3d aquarium screensavers but it is well worth the investment if you are looking for a truly interactive and fun educational experience.