The lionfish is a venomous marine fish native to the Indo-Pacific, and was likely introduced to the western Atlantic by people discarding the unwanted contents of their marine aquaria into the ocean. With no natural predators in the Atlantic, and a varied and voracious appetite, the lionfish invasion is now considered to be one of the most serious threats to Caribbean and Florida coral reef ecosystems. The larva (pictured here), is pelagic, and can drift out in the ocean currents until it matures, which means lionfish can be quickly distributed far from the source population.
The photo was taken in Palm Beach, Florida during a "black water dive" where the boat goes out several miles off shore at night into relatively deep water (400 to 500 feet). The divers look for bioluminescent creatures, jellies, squid, planktonic critters and the larval stages of many creatures, including this lionfish larva, that drift into their lights. The larva is about 1 cm in length.
Steven Kovacs, Immersion Photography, Palm Beach, Florida