Weedy Scorpionfish (Rhinopias frondosa)
The Weedy Scorpionfish (Rhinopias frondosa), also known as the Weedy Rhinopias, is a rare and highly sought-after species in the marine aquarium trade. Its elaborate appearance, with frilly appendages and intricate camouflage, makes it one of the most unique scorpionfish species. Native to the Indo-Pacific, including the waters around Japan, Indonesia, and Australia, it inhabits coral reefs, rubble zones, and sandy bottoms, often blending seamlessly with its surroundings.
Key Information
• Small fish safe ❌ No (predatory, will consume smaller fish)
• Small invertebrate safe ❌ No (actively hunts crustaceans and other invertebrates)
• Coral safe ✅ Yes (does not feed on corals)
• Minimum tank size 265 litres (70 gallons)
• Adult size Up to 25 cm (10 inches)
• Diet Carnivorous, feeding on small fish and crustaceans
• Be aware of Venomous spines; slow-moving ambush predator; requires live food initially
Appearance and Colouration
The Weedy Scorpionfish is one of the most visually striking scorpionfish species, known for its textured body and camouflage adaptations.
• Body Colouration
Highly variable, ranging from red, purple, yellow, brown, pink, green, or black, often matching their environment.
• Skin Appendages
Covered in leaf-like appendages and skin flaps, helping them blend into their surroundings.
• Size
Can grow up to 25 cm (10 inches), making them one of the larger Rhinopias species.
Natural Habitat and Behaviour
In the wild, Rhinopias frondosa is found in rocky reefs, coral rubble zones, and sandy seabeds at depths ranging from 10 to 100 metres.
• Ambush Predator
They remain motionless for long periods, waiting for unsuspecting prey to come within striking distance.
• Nocturnal Behaviour
More active at night, using their excellent camouflage to surprise prey.
• Solitary Lifestyle
Typically solitary, preferring to remain hidden rather than interact with other fish.
Tank Requirements and Water Parameters
• Minimum Tank Size 265 litres (70 gallons)
• Water Parameters
• Temperature 24°C – 26°C (75°F – 79°F)
• pH 8.1 – 8.4
• Specific Gravity 1.020 – 1.025
• Aquascaping
• Provide live rock, caves, and crevices for hiding.
• Open substrate areas for ambushing prey.
• Lighting Moderate to low, reflecting their deep reef habitat.
• Water Movement Low to moderate, as they are not strong swimmers.
Important Note: This species requires excellent water quality, as it is prone to bacterial infections if exposed to poor conditions.
Diet and Feeding
Weedy Scorpionfish are ambush predators that require live food when first introduced to captivity.
• Preferred Diet
• Live small fish, shrimp, and crustaceans.
• Once acclimated, they can accept frozen silversides, squid, and krill.
• Feeding Frequency
2–3 times per week, ensuring prey size matches their mouth opening.
Training Tip: Use feeding tongs to offer food, gradually transitioning them to frozen diets.
Compatibility and Social Structure
• Temperament
• Non-aggressive but will consume any fish small enough to fit in its mouth.
• Tank Mates
• Suitable with large, non-aggressive species such as tangs, angelfish, and larger wrasses.
• Avoid keeping with small fish, shrimp, or crabs, as they will be eaten.
• Multiple Rhinopias?
• Can be housed together only in large tanks with plenty of hiding spots.
Important Considerations
• Venomous Spines
• The dorsal, anal, and pelvic spines contain venom that can cause intense pain, swelling, and nausea.
• If stung, immerse the affected area in hot water (as hot as tolerable) and seek medical attention if symptoms persist.
• Tank Security
• Ensure a stable, stress-free environment, as these fish do not handle frequent disturbances well.
• Acclimation
• Often require live food initially, with gradual transition to frozen options.
Summary
The Weedy Scorpionfish (Rhinopias frondosa) is an extraordinary and rare species, best suited for experienced reef keepers who can meet its specialised care needs. With proper feeding, stable water conditions, and careful handling, it makes a fascinating centrepiece for a well-maintained marine aquarium.