In the video, the goldfish is sucked into the suction port of the filter in the fish tank, causing the fish to die from lack of oxygen. This footage was filmed by Mr. Dong, in Baiyun, Guangzhou, ...

But in your home tank, there's no bacteria to be found. You have to introduce it, and that's where a lot of goldfish owners slip up because you can't just buy a fish the same day you get your tank.