This is what it looks like when the red-bellied pacu fish and its pals go after a turkey leg. The pacu is a relative of the deadly piranha, although it has a reputation that arguably makes it more formidable even than the fish that gave us a series of comically violent, exploitative, b-level horror films: Amazonian locals know it as a “testes eating fish”.

Yes, the pacu is renown for its predilection for human testicles. And now it’s here.

That’s at least according to this article in the UK Metro, in which an aquarium curator speculates on the fish’s sudden appearance in non-native waters:

‘My theory is that during the holiday, someone who had the fish in an aquarium at home set it free.

‘They make excellent pets. The only problem is they grow too big for people’s home aquariums. Many people mistake the fish for piranhas, and many pet stores sell them as piranhas.

Testes eating fish as pets, of course! It all makes sense now. Stay out of the water, folks, possibly forever.