Although the spiky fins are not a threat to its prey, the venom of the lion fish can be lethal to predators and dangerous to humans. Lionfish come in second for the greatest number of stings annually. In a year, there are 40,000-50,000 people who report getting stung by a lionfish throughout the world. The sting of a lion fish lasts for fifteen to twenty minutes and has a firing burn. In some cases the sting of a lionfish may hospitalize victims or even result in death. There is currently no anti-venom to this sting.
Source 4 (Picture)
Source 5 (Video)