This a typical tabloid nonsense story. Despite the story being about pacus they show photos not of pacu’s teeth, which presumably is what people might be actually interested in, but a photo of piranha’s teeth – because it’s a close relative. Well the neon tetra is also a relative yet no photos of pretty neon tetras, I wonder why ?
There hasn’t ever been a single reported testicle eating incident in the pacu’s Amazon Basin home, and the entire “ball cutter” nickname appears to originate from the claims of one fisherman in Papua New Guinea, who apparently managed to make a positive identification despite just having his balls ripped off.
I don’t know what temperature and salinity the water in Sweden’s Oresund Sound has but I would be amazed if a fish which has evolved to live in the Amazon Basin survived for more than a few hours there.