Lionfish are the common name for many similar fish in the genus Pterois. Lionfish are beautiful looking aggressive predatory fish that are often kept in home marine aquariums as pets.
Red lionfish (Pterois volitans), Ripley’s Aquarium of Canada.
Lionfish originate in the Indo-Pacific but now they have become invasive species in the Caribbean, and along the East Coast of the United States, quickly decimating the native fish species. Apparently some pet lionfish specimens either get released into the wild or got loose during a hurricane and they started to multiply like rabbits. A reminder why pets should not be released into the wild.
Lionfish are rarely preyed upon by local predators. This might be partly due to the fact that the fin rays of the lion fish are connected to venom glands and anyone touching a lionfish can easily get envenomated. The venom rarely kills a healthy grown up human, but it is still very painful. Weaker individuals, the elderly, children, or people who are allergic to the lionfish venom can get killed by lionfish. This makes one wonder why do people keep lionfish as pets — must be their beauty, because they are certainly not cuddly animals.
Humans can and do eat lionfish, apparently it is rather tasty. On the other hand I only know about expensive lionfish dishes, or one might have to hunt down a lionfish with a spear and cook it themselves. Since various lionfish are considered to be invasive species, in most places it is legal, or even encouraged to kill them and eat them.
Further Readings:
Red lionfish on Wikipedia.
Lionfish Care Guide.
The Truth About Getting Stung by a Lionfish.
Eating Lionfish on lionfish.co.