From the diagram, I'm guessing the fish's water output & recharge input is actually a self contained loop, the design just creates the illusion of starving the fish. The article doesn't do a good job of explaining this. - Graham Sergeant

"There is a traditional shaped fish bowl in the Poor Little Fish basin. While using, the level of water in the bowl gradually falls (but does not actually drain out); it will go back to the same level once the water stops running. As well, the water from the tap is pure, as its pipeline does not connect to the bowl." http://www.yanlu.com/ - Graham Sergeant