Red Lionfish (Pterois volitans)
The Red Lionfish (Pterois volitans), also known as the Common Lionfish, is a venomous and highly distinctive marine fish native to the Indo-Pacific. Recognised for its bold stripes, flowing fins, and venomous spines, this species has also gained notoriety as an invasive species in the Atlantic and Caribbean, where it has disrupted local ecosystems.
Key Information
• Small fish safe ❌ No (highly predatory, will consume smaller fish)
• Small invertebrate safe ❌ No (actively hunts crustaceans and small invertebrates)
• Coral safe ✅ Yes (does not directly feed on corals)
• Minimum tank size 400 litres (105 gallons)
• Adult size Up to 38 cm (15 inches)
• Diet Carnivorous, feeding on fish, crustaceans, and cephalopods
• Be aware of Venomous dorsal spines; can become an invasive threat if released into non-native waters; requires experienced reef keepers due to its specialised care needs
Appearance and Colouration
The Red Lionfish is one of the most easily recognisable marine species, with its dramatic appearance characterised by:
• Colouration
A white or cream-coloured body marked with bold, reddish-brown vertical stripes.
• Fins
Large, fan-like pectoral fins and elongated, venomous dorsal spines.
• Size
Adults can reach up to 38 cm (15 inches) in length, with some specimens growing even larger in the wild.
Natural Habitat and Behaviour
In its native range, the Red Lionfish inhabits reef environments, often at depths between 1 and 50 metres. Preferring rocky crevices, caves, and coral overhangs, it is primarily nocturnal, emerging at night to hunt small fish and crustaceans. Lionfish use their large pectoral fins to corner prey before swallowing it whole.
• Solitary or Small Groups
Red Lionfish are typically found alone, but juveniles may form small aggregations.
• Slow but Efficient Predators
Despite their slow movements, Lionfish are highly efficient ambush predators, using their fin displays to confuse and trap prey.
Tank Requirements and Water Parameters
• Minimum Tank Size 400 litres (105 gallons)
• Water Parameters
• Temperature 24°C – 28°C (75°F – 82°F)
• pH 8.1 – 8.4
• Specific Gravity 1.023 – 1.025
• Aquascaping
• Provide plenty of caves, rock formations, and shaded areas to mimic their natural reef habitat.
• Open swimming space is essential to accommodate their large fins and hunting behaviour.
• Lighting Moderate, with dim or shadowed areas to replicate their natural daytime hiding spots.
• Water Movement Moderate, mimicking reef conditions.
Important Note: Lionfish must be housed in secure tanks, as they can be dangerous to handle due to their venomous spines.
Diet and Feeding
Red Lionfish are carnivores that consume a variety of live and frozen meaty foods. In captivity, they may need to be weaned off live food.
• Captive Diet
• Offer a mix of fresh seafood, such as shrimp, squid, and fish fillets.
• Vitamin-enriched frozen foods, including mysis shrimp and silversides.
• Avoid feeding freshwater feeder fish, as these do not provide proper nutrition.
Feeding Frequency: 3–4 times per week, offering portions appropriate to their size.
Compatibility and Social Structure
• Temperament
• Generally peaceful towards similar-sized tank mates, but will consume anything that fits in its mouth.
• Should not be housed with small fish or crustaceans.
• Tank Mates
• Best suited to large, non-aggressive species such as groupers, tangs, and larger wrasses.
• Avoid housing with other predatory species unless the tank is exceptionally large.
• Multiple Lionfish?
• While possible, housing multiple Lionfish together requires a large, well-structured tank to prevent territorial disputes.
Important Considerations
• Venomous Spines
• The dorsal, pelvic, and anal spines contain venom that can cause intense pain, swelling, and nausea if stung.
• If envenomated, immediately soak the affected area in hot water (as hot as tolerable) and seek medical attention if symptoms worsen.
• Invasive Species Concerns
• In the Atlantic and Caribbean, where they have no natural predators, Red Lionfish populations have exploded, decimating native fish populations.
• It is illegal and environmentally damaging to release Lionfish into non-native waters.
• Acclimation
• Lionfish can be sensitive to changes in water parameters, requiring a slow, careful acclimation process.
Summary
The Red Lionfish (Pterois volitans) is a stunning yet high-maintenance species, best suited for experienced reef keepers. While its graceful movement and dramatic appearance make it a popular choice for large marine aquariums, its venomous spines and predatory nature require careful planning. Additionally, its status as an invasive species in many parts of the world serves as a reminder of the importance of responsible marine fishkeeping.