Initially all but ignored by native predators, the beautiful but venomous lionfish — an Asian native — has been spreading widely and rapidly throughout eastern U.S. waters and the Caribbean since being introduced through the aquarium trade. However, an international research team now finds that lionfish densities are amazingly low in the Exuma Cays Land and Sea Park in the Bahamas, apparently because the invasive fish has become a favored lunch of the native grouper. As a result of a 20-year fishing ban in the park’s waters, huge groupers exist at high densities there, the scientists report June 23 in PLoS ONE. The researchers argue that the situation illustrates a need for fishing controls that would spare large groupers, one of the few natives with a proven appetite for lionfish. Some lionfish escaped into the wild in 1992 when Hurricane Andrew broke an aquarium in Miami. Scientists suspect many additional introductions were deliberate.