The Indian Ocean and Red Sea lionfish, separated from the red lionfish on fin-ray counts. Introduced and invasive in the Atlantic.
To about 35 cm, banded in red-brown, white and dark brown, with very long separated pectoral fin rays and long venomous dorsal spines. It is the Indian Ocean and Red Sea counterpart of the red lionfish and the two are separated on fin-ray counts rather than on anything visible underwater. Where the ranges do not overlap, the ocean settles it.
It hunts at dusk and after dark, herding small fish against a wall or a coral head with the spread pectoral fins and then taking them with a fast strike. By day it hangs under an overhang or inside a wreck, frequently upside down against the roof, which is where a diver’s head goes. The dorsal spines are venomous and the sting is severe — intense pain, swelling, and occasionally systemic effects. Hot water is the accepted first aid and it is not a substitute for a doctor. The fish does not attack; it holds its ground and points its spines at whatever is approaching, which is why the injuries are to hands and to the tops of heads.
Together with the red lionfish this species is the Atlantic invasion. Both were introduced to Florida waters in the 1980s and have spread through the Caribbean, where they have no predators that recognise them and where they eat juvenile reef fish in quantity. Culling programmes run in several countries, including the Cayman Islands.
Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.
