Volitans Lionfish

With its red-brown and white vertical stripes, long pectoral fins with separated rays and dorsal spines that stand up like a mane, the lionfish is the best-known predator of the marine aquarium. It swims slowly and deliberately, gliding along, corners its prey with its pectoral fins and swallows it in a single strike.

Venomous spine warning: the spines on the dorsal, pelvic and anal fins carry venom glands. A sting is very painful and can cause swelling and nausea. Wear gloves during maintenance and always know where the fish is. If stung, soaking the wound in water as hot as can be tolerated (around 45°C, without scalding) for 30–90 minutes eases the pain; always seek medical care.

Do not release into the wild: lionfish, thought to have escaped from aquariums, have caused a major invasion in the Western Atlantic and the Caribbean. Its close relative Pterois miles, which entered the Mediterranean through the Suez Canal, is also spreading rapidly along the coasts of Türkiye. Aquarium fish are never released into the wild under any circumstances. Because P. volitans and P. miles look very similar, they are often sold under the same name in the trade; their care is the same.

It lives on Pacific reefs, in lagoons and in rocky areas. By day it rests under overhangs; at dusk it hunts small fish and shrimp.

• Volume: at least 500 liters and 150 cm of length.
• Water: salinity 1.020–1.025 specific gravity, pH 8.1–8.4, temperature 24–27°C. Since it is a large, messy eater, strong filtration and a protein skimmer are needed.
• Decor: overhangs and caves to rest under, with open space in front.
• Reef compatibility: reef safe with caution: it does not touch corals, but it eats shrimp and any fish that fits in its mouth.

Carnivorous. In the wild it eats live prey; in the aquarium it must be weaned onto thawed seafood (shrimp, fish flesh, squid, mysis) using a feeding stick. Live freshwater feeder fish (guppies, goldfish) carry disease and cause fat buildup; they should not be given. Juveniles are fed once a day, adults 3–4 times a week.

It is not aggressive toward other fish, but it is a predator: any fish that fits in its mouth counts as prey. Nipping species such as triggerfish and large pufferfish may damage its fins.

Good companions: calm, large fish that do not fit in its mouth: tangs, large angelfish, foxface, large wrasses, moray eels, other lionfish.

Avoid: small fish and shrimp, seahorses, fin-nipping species.

Usually kept as a single individual. In a large aquarium several lionfish of similar size can live together; if the size difference is large, the smaller one may be eaten.

In the wild the male courts the female, and the female releases her eggs in floating balloons of mucus. It does not breed in home aquariums.

• Fatty liver: seen with excessive and fatty feeding.
• Shedding: it is normal for it to occasionally shed the outer layer of its skin like a thin film.
• Copper sensitivity: it is sensitive to copper treatment; take care when choosing a treatment.

Hard to tell apart externally; mature males may be slightly larger and color up darker in the breeding season.