Natural predators in the Indo-Pacific and the Red Sea (where lionfish are indigenous) known to eat lionfish include sharks, grouper, giant eels, frogfish, and scorpionfish.
However, there are no known natural predators in the areas where lionfish are invasive. These include the Caribbean, Atlantic, Gulf of Mexico, and the Mediterranean. Divers are encouraged to spear as many as possible.
In the Indo-Pacific and the Red Sea, marine life has had hundreds of years to learn to eat the lionfish. However, in the other areas, they have been invading, it’s been less than fifty years for the larger fish to know they can eat them.