Lionfish may be beautiful, but their arrival in Caribbean waters was disastrous for marine life in the area. Jim Hart, co-founder of Lionfish University, recorded what is thought to be the first piece of footage of a grouper eating an invasive lionfish without human intervention. The astonishing video was filmed off the coast of the Cayman Islands, but the lionfish invasion has now stretched as far south as the Venezuelan coast. Credit: YouTube/Lionfish University

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