With its vivid coloration and poisonous spines, this scorpionfish species effectively deters predators and, consequently, can swim freely without fear of attack. The lionfish is a type of scorpionfish. Its beautiful fins conceal an array of poisonous spines capable of inflicting severe pain. Like many scorpionfish, it does not have many predators, since few animals will dare to attack it.

Habits: The lionfish lives in shallow water among the rocks and coral reefs of warm and temperate seas. Its featherlike fins and bristling spines are not merely decorative but, rather, serve as camouflage that helps protect the fish among the seaweed and coral on the seabed. The lionfish spends most of its time lurking or resting among the rocks on the bottom of the seabed. It is rarely detected unless it moves. This behavior is typical of most scorpionfish (members of the Scorpaenidae family). Unlike the lionfish, some other species of scorpionfish do not hide but, rather, swim through the water seemingly indifferent to predators. 

They have poisonous spines and, like brightly colored wasps, they advertise the presence of the spines with their gaudy coloration. Would be predators seem to recognize the possible danger and avoid swimming too close. As a result, the scorpionfish is virtually immune to attack by other fish. The lionfish is one of the few aggressive scorpionfish. It will raise its spines, point them at an intruder, and even advance threateningly.

Breeding: Most fish lay eggs. Many produce millions at a time, leaving them to the ocean currents and to predators, so that only a small proportion survive to maturity. Some scorpionfish species, including the lionfish, have large numbers of eggs that reach maturity. These fish are ovoviviparous (the eggs stay in the female’s body until they hatch), ensuring that the eggs are safe. Still, when the hatchlings are released into the water, many fall prey to other fish.

Several thousand young must be produced each season so that a sufficient number will survive. The Californian scorpionfish and some tropical species also lay eggs. The eggs are embedded in a large, hollow, gelatinous balloon that floats on the water’s surface. As soon as the young hatch, they sink rapidly to the seabed to avoid being eaten by predators.

Food and Feeding: The lionfish eats any fish and crustaceans it can catch. It expends a great deal of energy chasing its prey, so it must eat a large amount to compensate for this loss. Still, like all predators, the lionfish has an instinctive awareness that causes it to give up the chase if it seems likely to use more energy than it is worth. Some species of scorpionfish are bottom dwelling and remain motionless and virtually invisible when not feeding. Its inactivity uses up little energy, so a single feeding will sustain the fish for several days. A lionfish opens its mouth wide, and its prey floods in with the water.

Defense: Scorpionfish spines are barbed and dagger sharp, and each has an elongated poison gland. The more elaborately finned shallow water species are the most poisonous. The effect of the poison on an animal can be fatal. Lionfish venom is a neurotoxin, or nerve poison, and when injected into a predatory fish, it paralyzes its muscles – including its heart. For a human, the consequences are usually less drastic, but still extremely painful. The stonefish is a close relative of the lionfish. Its harmless appearance disguises venomous spines that are lethal to humans.

Key Facts:
Sizes:
Length: Lionfish grow to 15 in., with pectoral fins spanning 30 in.

Breeding:
Mating season: Spring for temperate species
No. of young: Up to 20,000 in some species

Lifestyle:
Habit: Solitary. Lionfish are free swimming; other species are mainly bottom dwellers
Diet: Smaller fish, small crabs, prawns, and shrimp

Related Species: There are 300 species of related scorpionfish, found mainly in the Indian and Pacific Oceans, but Sebastes marina, the redfish or ocean perch, is found throughout the north Atlantic.
Distribution: Reefs and coastal shallows in the Indian and Pacific oceans, from eastern Africa to New Guinea, Australia, the Philippines, and the western Pacific islands.
Conservation: Despite some commercial collection for aquariums, the lionfish is in no immediate danger.

Special Features of the Lionfish:
Pectoral fins: Spread wide and used to rake through the water, sweeping smaller fish into a position where they can be eaten.
Spines: If the spines are thrust into an attacker, the venom in the glandular tissue is squeezed up a groove into the wound, where it enters the bloodstream.
Mouth: The wide mouth of the lionfish is used as a trap. When suitable prey swims past, the fish opens its mouth and water floods in, drawing the helpless prey in with it.

Did You Know: 
An Indian species of scorpionfish has a symbiotic, or mutually beneficial, relationship with the hydroid (a small species resembling the sea anemone). The hydroids attach themselves to the skin of the scorpionfish and provide it with camouflage. In return, they are transported by the fish.
The closely related stonefish is the most  poisonous fish in the world. Its 13 dorsal spines deliver a poison that can kill a person in six hours.

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