The a-pacu-lypse is upon us. As if US waterways weren’t teeming with enough invasive fish of late, a Texas angler caught a South American piranha relative with “human teeth” at a local lake on Sunday.

A new species of piranha-like fish called pacu was recently found hiding in plain sight among several near-identical species in the Amazon River. Researchers have named it after Sauron from "The Lord ...