The Blue Realm - Toxic Invaders 9

They're beautiful - and deadly, with venomous spines that resemble a lion's mane. They're lionfish, a tropical reef species normally found in the Indo-Pacific. Now, they're wreaking havoc in the Caribbean and Atlantic - all thought to have descended from a handful of aquarium fish carelessly released into the sea. In these regions, they are potentially a greater threat to coral reefs and commercial fish populations than global warming or pollution. In the Florida Keys, some practical and novel approaches are making progress in the fight against these Toxic Invaders.