Lionfish (Pterios) are one of the most beautiful fish that you’ll see while snorkeling in Thailand. There are 9 species native to the indo-pacific region. As with a lot of sea creatures bright and beautiful can often equate to dangerous as well. Lionfish tentacles (dorsal fins) are highly poisonous.
It is unlikely (but not unheard of) that a fit human adult will die from a lionfish sting but extreme pain, fever like symptoms, headache, dizziness, diarrhea and difficulty breathing are all known effects. Cases of aggression towards scuba divers has been recorded although most stings are to fishermen.
Lionfish use their venomous tentacles for defence from predators, not for catching their prey. To hunt, lionfish lay in wait until their prey is near enough for them to lunge forward and swallow their prey in a single bite. Lionfish mainly eat small fish and crustacians which they can corner by opening out their fins. Lionfish have also been observed blowing jets of water at their prey, presumably to disorientate them. Lionfish are most active hunters in the morning from sunrise to before midday.
Lionfish have few predators apart from sharks, large groupers and moray eels. This has caused a problem in the Caribbean where lionfish are not endemic but were accidently introduced into the habitat and are over running native fish populations. Because of their beauty lionfish make popular aquarium fish and it is thought that released aquarium fish in Florida may have caused their introduction to the Atlantic.
Lionfish have very well adapted swim bladders which allow them to move up and down the water column as well as back and forward.
Lionfish can live to over 15 years old. Their beautiful tentacles are also thought to play a role in courtship behaviour. Females can release 15,000 eggs at one time which are then fertilized by the male. The small fry hatch in open water two days later and float in the water column until they are a few centimetres long and strong enough to swim to the sea bed.