Swedish men are in a state of testicular trepidation as a cousin of the piranha fish with, apparently, a taste for biting men’s testicles, has been spotted in local waters. A museum official unleashed the panic by issuing a “Watch Your Testicles” warning.

The fish in question is called the pacu, a species that shares a close resemblance to the piranha, not least in its rather terrifying looking teeth. Generally found in the waters of the Amazon and Orinoco river basins, it usually enjoys temperatures warmer than those of the Scandinavian shoreline. Despite this, a fisherman on August 4 pulled a 21cm pacu from the Oresund Strait in the southern Swedish province.

For non-English speakers, these are what we're worrying about.

Despite its powerful jaws, the pacu mainly subsists on a vegetarian diet, with a particular fondness for nuts from trees. Sadly, however, theycan show a lack of discrimination and have been known to turn to the body parts of South American fisherman. That fondness for nuts is clearly a worry. Rumour has it that they’ve earned the rather alarming nickname “ball cutter” after apparently castrating a few unfortunate fisherfolk.

Another unfortunate victim?

How did the fish get into Scandinavian waters? Probably because some nutter chose to empty his ornamental fishbowl into the ocean. This is probably not a first as, last year, it was reported that two pacu fish were spotted in Lake Lou Yaeger, Illinois, USA.. A video report follows.