At Undersea and Hyperbaric Medical Society (UHMS) 2013, Dr. Dario Gomez, one of DAN’s referral physicians, presented 33 cases of divers stung by lionfish in Cozumel over a period of three years. Most injured divers (21) were participating in lionfish culling tournaments and were stung while handling the catch, seven were trying to catch the fish and only five were stung accidentally. All were stung in their hand.
Lionfish is a beautiful fish native to tropical reefs of Indian and Pacific Oceans, which in recent decades has spread to the Atlantic. It is a predator that eats many other species and, without a natural enemy in Atlantic, it is a threat to the reef ecosystem. Thus, in many areas divers have organized fishing tournaments with the goal of limiting populations of this invasive species. Lionfish have venomous spines used for defense. Some estimates put the annual worldwide number of lionfish stings at 50,000 worldwide, which is second only to stingrays. The number seems very high, but the fact that lionfish are frequently kept in home aquariums and that divers chase them deliberately, may explain the number. DAN offers safety tips for divers who plan to participate in these tournaments.
The spines of lionfish deliver a venomous sting causing burning pain that can last for days and may be accompanied by sweating, respiratory distress, and other symptoms including even paralysis. The venom is a combination of protein, a neuromuscular toxin and a neurotransmitter called acetylcholine. The toxin is denatured by heat and immersion in hot water bath (114F, 45C) is a recommended first aid measure.
All of the patients in reported series were treated with immersion of the stung hand in a nonscalding hot bath and non-steroidal anti-inflammatory drugs (NSAIDs). All patients responded well to the hot water. In addition, they received wound treatment and were advised to seek tetanus prophylaxis. No complications were reported. The sting did not appear to discourage divers from participating in lionfish fishing tournaments, since nine were stung more than once.
Be aware that lionfish sting may have more serious consequences in small children and in adults with cardiac conditions or a compromised immune system.
Learn More:
“Extent and Speed of Lionfish Spread Unprecedented”
“Lionfish Tournaments: Safety Tips”
“Marine Envenomations: Vertebrates”
Post written by: Petar Denoble, MD, D.Sc.
The Dive Lab 
My personal observation suggests that hot air as from a hand held hair dryer works better than immersion in hot water.
Important to note that stings from _dead_ lionfish remain possible for a couple of hours, until the toxins in the spines break down. Any DAN research on exactly how long the poison retains its potency post-mortem? Sounds like an ideal area for data collection to me…
This is really an interesting question. We could ask this question to fishermen who handle hundreds of dead lionfish on a daily basis. It could also be addressed by a direct experiment, but at this time we have no resources to do it. Since the creature is dead, it should suffice to exercise caution when handling it.
These articles are great to read! I’m new to diving and the more I know the better I think!! 😀
Thanks for an interesting blog. Is the venom a tetrodotoxin-like substance like in puffer fish or blue-ringed octopus bites? Thanks. Donald Jacobson, MD, disabled diver/physician and now blogger for diver health and safety at – http://www.scubagearpro.com/blog