I bought a copy of this a few months ago, then lost my registration during a system crash. In the meantime, I got an ad for Allume's Aquazone, which offered more features and more cool fish, so I bought and downloaded that for $20. All I have to say is that 3D Aquarium is by far the better deal--Aquazone is a huge CPU hog, and has poor resolution. I agree that it would be cool if you could turn off the sound of the pump and just hear the water...