The lagginess of the webcam leads me to believe that it's real, also I saw a couple of fish stop and eat algae off of a rock. A 3D simulation (which the company does do) would hopefully have better performance.

Is it safe to feed fish every hour? That seems excessive.

I use to have this screensaver running, it's very nice. I'm not sure if it's been updated in a while though. http://www.dreamaquarium.com/