Testicle-biting fish invading Denmark, authorities warn

This red-bellied pacu recently caught in Denmark could be a sign that the fish is invading Scandinavian waters. (Henrik Carl)

Jaws may not be the only one salivating as you splash.

Just when you thought it was safe to go back in the water, a cousin of the piranha reported to go after swimmer's testicles has been found in coastal waters between Sweden and Denmark. And fish experts are warning locals to stay aware -- in order to stay whole.

"Keep your swimwear on if you're bathing in the Sound these days -- maybe there are more out there!" Henrik Carl, a fish expert at the Natural History Museum of Denmark, told Swedish news site The Local.

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"They bite because they're hungry, and testicles sit nicely in their mouth," Carl added.

Yikes!

The creature in question is a red-bellied pacu, and is native to the Amazon. Pictures of the freaky fish frequently make the rounds of inboxes because of its strangely human-looking teeth.

Local fisherman Einar Lindgreen caught the exotic species on Aug. 4 in the Oresund, the strait between Denmark and Sweden, according to LiveScience. The toothy chomper Lindgreen found was just 8 inches long, but the fish can grow to weigh as much as 55 pounds.

Though its teeth are used mainly to crush nuts and fruits, the pacu eats other fish and invertebrates and there have been some reports of human attacks. In Papua New Guinea, the invasive species has reportedly earned a reputation as the "ball-cutter" after castrating a couple of local fishermen, LiveScience said.

"It's the first time this species has been caught in the wild in Scandinavia," fish expert Peter Rask Mller of the University of Copenhagen said in a statement. "Discovering whether this fish is a lone wanderer or a new invasive species will be very exciting. And a bit scary."

"It is not unlikely that someone has emptied their fish tank into a nearby stream just before a vacation and that the pacu then swam out into the brackish waters of Oresund," Mller said.

Better tie those trunks extra tight, however -- just in case.