The discovery of what seems to be a piranha relative has prompted a wave of fear. The creature, although traditionally found in South American rivers, was found in a pond in South Jersey last weekend. Some worry that the find could suggest the spread of the invasive fish, a type of pacu, and represent a threat to ecosystems, whereas some male readers will be panicking that their crown jewels may no longer be safe.
Why? Pacus have earned the unfortunately ambiguous nickname “nutcracker fish,” or the slightly less equivocal “testicle-biting fish.” The former is attributable to the fact that these predominantly vegetarian fish use their freakishly human-like gnashers to chomp on hard foods like nuts and seeds.
The latter label they have been undeservedly slapped with came about after various articles reported on some alleged castration events in Papua New Guinea that left two men dead, supposedly at the jaws of pacus. But there isn’t any hard evidence to back up this claim, making it far more likely to be a rumor than a reflection of their taste for testicles.
But this fabled fancy for the male genitalia was not helped by the fact that the fish featured in a 2011 episode of Animal Planet’s “River Monsters” in which host Jeremy Wade described reports from local fishermen working in the area where the supposed attack took place. That, combined with the following joke made by fish expert Henrik Carl, was enough to fuel the fire: “They bite because they’re hungry, and testicles sit nicely in their mouth.” Consequently, the name has stuck.
Enough about names – back to the discovery. The fish was caught by Burlington County resident Ron Rossi on June 21 during a family fishing trip to Swedes Lake, South Jersey. According to WPVI, its appearance initially led them to believe it was a piranha, but after a good old Google session, the Rossi’s concluded it was probably a pacu based on its distinctive dentition.
“We did pull the bottom lip down to see what they looked like and they have almost human teeth,” said Rossi. “It’s exactly what it looked like on the Internet.”
Although it’s difficult to say how the fish ended up in an artificial lake in Jersey, the state’s Department of Environmental Protection (DEP) believes the story likely begins at a pet store. While the specimen only looks to be small, they can reach a meter (3 feet) in length and thus far outgrow the living space they are provided with.
“Many times, these fish are deposited into lakes by pet owners,” a DEP spokesperson said in a statement. “These fish do not survive in colder water, so we encourage people not to release it into the wild but to humanely destroy the fish.”
There are concerns that there could be more pacus lurking in the lake, but if they are not going around nibbling at nether regions, where does the worry stem from? The lake is often busy with swimmers, and there have been reports of pacu bites before, but the risk is probably slim. A greater worry is that they may upset lake ecosystems by outcompeting native species or introducing disease.