Lionfish are indigenous to the Indo-Pacific and Red Sea, but are now expanding rapidly in the Atlantic and Caribbean.

It is thought they were first introduced into Biscayne Bay, Florida, in 1992 from a private aquarium in a waterside home swept into the waters as a result of Hurricane Andrew.

While some blame aquarium owners for contributing to the problem by dumping lionfish when they outgrow their tanks, other theories suggest they may have been transported to the Atlantic through the ballast of ships.

They are now regularly sighted in the western Atlantic, from Long Island in the north down to Uruguay.

This year they were spotted in the Florida Keys for the first time and environmentalists now fear they will spread into the Gulf region.

Two species have been found in the Atlantic miles and volitans.

A female lionfish can lay up to 30,000 eggs at a time. The lionfish has no natural predators in the Atlantic, so most will survive to adulthood and continue the reproductive cycle.

They were first spotted in the Bahamas in 2004 and are now considered the most dominant fish in the waters of Nassau.

The population is so large it is estimated they are eating up to half a million fish in each square kilometre.

Not only is it threatening the country's fishing industry, destroying reef fish and fish stocks, but environmentalists fear the diving industry is now in peril as there may soon be nothing for vacationers to see but lionfish.

Lionfish eat commercial fish such as grouper and snapper juveniles, reef fish and crustaceans.

Swallowing up smaller fish who act as cleaning agents could also see larger fish wiped out due to parasites.

Scientists say the invasive species will also affect the health of coral reefs, by killing off species such as parrotfish which eat algae for example.

The first confirmed lionfish sighting in Bermuda was in 2000 when one was brought to the Agricultural Exhibition. It is thought the eggs had been carried on the Gulf Stream, with currents and eddies bringing it to our waters.

REEF (Reef Environmental Education Foundation) is actively trying to monitor the fish through tagging projects in the Bahamas.

It is also lobbying the US government for greater microchipping of domestic pets and a tougher stance on the importation of lionfish.

It is estimated 750,000 are imported to Florida each year alone for the pet trade.

Lionfish display their spines containing venom to discourage predators. They deliver a painful sting through the spines on their dorsal, anal and pelvic fins.

Heating or freezing them denatures the venom.

After a sting, swelling is almost instantaneous but placing the limb in very hot water will denature the protein in the venom.

The pain described as similar to a bee sting but slightly nastier, usually wears off after an hour. However, anyone stung should seek medical attention.