It is funny that you mention this - there was this one case in Scotland:
" They've also been known to bite humans when they mistake someone for food.
For example, a toddler was bitten by a pacu fish at an aquarium in Scotland, but officials say that it wasn't a sign of aggression. The fish just saw her wiggling fingers as bait.
Pacu fish have also made headlines for biting at the nether regions of men, but this is mostly an exaggeration. There's only been one confirmed report of a man receiving a pacu bite. Most of the pacu fish's reputation as a “ball-cutter” comes from sensational media reports.
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