In the video, Louis Cole, 28, laughs as he looks into the camera, saying he is going to “eat his pet goldfish”.

He then grabs the four-inch long fish from its bowl. Despite the goldfish’s desperate attempts as to get free, Cole puts it into his mouth and bites, and a crunching sound can be heard.  

Cole struggles to eat the fish, but soon swallows the helpless creature. He says in the video: “That was really, really bitter - the most bitter thing I've ever eaten.”

The stunt has been watched by more than 120,000 people.

The former youth worker, who lives in Roehampton, south west London, is now being investigated for animal cruelty after posting the video online a fortnight ago. If the RSPCA decided to prosecute, he could face up to six months in prison.  

Previous stunts by Cole, who prides himself of being able to eat almost anything, include eating a live tarantula, a scorpion and 10 ground up dead mice.

The RSPCA previously condemned Cole's actions, but could not launch an investigation as all the animals he ate before the goldfish were invertebrates.

Cole published on Facebook a letter he received from the animal welfare charity, informing him that he was being investigated for causing unnecessary suffering to an animal under the Animal Welfare Act 2006.

The letter said he was also being investigated for breaching the duty of a person responsible for an animal to ensure its welfare.