Sea Monkeys inventor made thousands from selling fish that never actually existed

The inventor of Sea Monkeys reportedly made thousands after selling 'invisible' fish that didn't exist.

Selling a product that doesn't actually exist is usually known as fraud, right?

But somehow, Harold von Braunhut - the inventor of Sea Monkeys - got away with selling 'invisible' fish for several years.

Sea Monkeys were, however, his biggest money maker.

The little brine shrimp things could be added to water, and fascinated kids would watch them grow.

The packaging stated that Sea Monkeys would last only for 'several months', but with the right care - they could actually last for up to five years.

The 'invisible' goldfish, on the other hand, had a zero-year lifespan, because they weren't actually real.

It's literally just an empty fish bowl. (Sea Monkeys)

And while the American inventor promised that people would never see the fish, they were purchased in their thousands.

Worst of all, von Braunhut also happened to be massively racist.

The businessman sold weapons to the Ku Klux Klan, and was a regular attendee at white supremacist meetings.

Once interviewed about the claims, he said: "You know what side I'm on. I don't make any bones about it."

Despite growing up in a Jewish household, a former business associate also said that von Braunhut had once told him: "Hitler wasn't a bad guy. He just received bad press."

And to everyone's surprise, the non-existent fish are still in circulation.

So if for whatever reason you want to buy an empty fishbowl and feed the 'invisible' fish, it is actually still an available product.

But of course you could just throw together the contraption by yourself.

Sea Monkeys were a staple of a lot of people's childhoods. (Wikimedia Commons)

All you need is a goldfish bowl filled with water...and a vivid imagination.

Slightly later in life, von Braunhut took a different approach to his creations.

He released a different kind of product - the Kiyoga Agent M5.

And while people were used to his comical creations, this was a whole different genre.

It was branded as a self-defence tool for people who didn't have a gun license.

The weapon was pen-sized, complete with a coil-spring that unfurled a metal whip at the flick of a wrist.

He sold the self-defence tool for $59.95 - and they were popular.

Braunhut died on November 28, 2003 after falling, but the exact cause of his death is still unknown.