In the 1980s, aquarium lovers apparently released red lionfish, a showy predator from the Pacific, into the waters off Florida. Since then, the species has spread dramatically, appearing as far north as New England. It has also invaded the Caribbean, where it has exacted a heavy toll on native reef fish. Now, new research shows that carefully targeted hunts by divers can reduce lionfish numbers enough to allow native populations to rebound. The studies show you don't have to kill every last lionfish to make a difference.