Pacu Teeth
There have been incidents in other countries, such as in Papua New Guinea, when the pacu, a relative of the piranha, had bitten off testicles. YouTube

A half-joke warning for men fond of skinny dipping to be careful of the pacu may have some truth in it. And with the “testicle-eating fish” spotting moving from New Jersey to Paris, warning is now being given to Brits because the pacu could be headed next for the United Kingdom.

Over the weekend, British tabloids report that the pacu is headed likely for the country due to dumping by owners of the fish in local canals and rivers by home aquarium owners who got tired of the fish. It could also swim toward Britain after reports also came out that the fish has been sighted in France and Denmark.

A fish exert, Dan Harding from the Sweet Knowle Aquatics in Stratford, debunks the speculation that human male crown jewels are not safe from the pacu. He says the fish is mainly herbivorous, or a plant-eater, not a flesh-eater. It feeds mainly on seeds, fruits and nuts as well as insects and small fish.

In the Amazon River, where it is endemic, the pacu chomps on Brazilian nuts from overhanging branches of trees on rivers. Whether the fish is purely herbivore or carnivore is not that important for Brit males because it is a tropical fish, the pacu would likely not survive in the cold waters of Britain as it requires temperatures between 72 and 82 degrees Fahrenheit, says Harding, reports The Telegraph.

But the discovery of the fish in Denmark made some scientists realise that the pacu has a wide range of environmental tolerances in terms of water temperature or salt content. Dr Daniel Merrifield, Fish Health and Nutrition lecturer at Plymouth University, points out, “It is quite possible that the pacu could mistake human testicles for nuts or fruits – or large seeds.”

Pacu
Because it is a tropical fish, the pacu would likely not survive in the cold waters of Britain. Wikipedia

The scientist who originally warned men from swimming naked in rivers, Dr Peter Rask Moller, fish expert at the University of Copenhagen in Denmark, admitted to CNN that his warning was half-joke when reports surfaced in Denmark of the discovery of a pacu in national waters. He then warned, “Male swimmers should keep their pants on in case there are more pacus out there in our cold Baltic waters.”

Henrik Carl, another fish expert, adds that there have been incidents in other countries, such as in Papua New Guinea, when the pacu, a relative of the piranha, had bitten off testicles, reports Local in 2013. In South America, local fishermen that were victimised by the pacu bit had bled to death after they lost their testicles to the fish, reports The Independent.

However, Marine Conservation Society’s Richard Harrington debunks that pacus are dangerous to humans, particularly when it is introduced into new waterways which causes ecological havoc. He cautions aquarium owners from dumping their unwanted pacus in waterways and adds that other marine creatures, such as the jellyfish and weever-fishes also bite men’s nuts, but that does not prevent them from swimming au naturel.

“If you’re particularly concerned, wearing beach shoes and wetsuits will minimise the risk of danger even further,” Harrington states.