This video made the rounds on the goldfish forum....it's a joke. Unfortunately the goldfish would develop sores where the devise is touching it. My goldfish developed swim bladder and used to wedge himself behind a decoration to stay put. Within a day he had developed sores.
To the folks who mentioned tank size, thank you
. One goldfish needs 20 gallons. each additional goldfish is 10 gallons....but some forums recommend 20 gallons. I can vouch for 4 goldfish in a 50 gallon is over stocked. I'm WC every 3 days. My goldfish gang is nick named the turds for a reason. My 1 inch goldfish is now 4 inches...all in 10 months. That cute goldfish grows really fast.
Though I'm not sure all goldfish experts would agree, long term exposure to high nitrates can irritate the swim bladder and cause floaty issues.