Quite the tank and what a mass of fish. I agree with CRM that it could be decieving on the size of the tank but what a video.
At Point Defiance Zoo and Aquarium, when they feed the fish it is like there is no room for anything but when things calm down it barely looks like there is a fish in the tank. The fish have like double the tank capacity that is under the viewing area so it can be very deceptive. That tank actually looks like it was feeding time and that it could be 2-3x what is shown.
I will say this, I didn't know clown fish came in so many colors!