Weedy Scorpionfish (Rhinopias frondosa)
The Weedy Scorpionfish (Rhinopias frondosa), also known as the Lacy Scorpionfish, is one of the most sought-after species in the Scorpaenidae family. Found in the Indo-Pacific, this benthic predator is known for its elaborate frilly appendages, which enhance its camouflage among coral and algae-covered reef environments. Its striking coloration, venomous spines, and unusual locomotion make it a fascinating addition to public and advanced private aquariums.
Key Information
• Small fish safe ❌ No (will prey on small fish)
• Small invertebrate safe ❌ No (will consume small crustaceans)
• Coral safe ✅ Yes (does not harm corals)
• Minimum tank size 250 litres (65 gallons)
• Adult size Up to 23 cm (9 inches)
• Diet Carnivorous, feeding on small fish and crustaceans
• Be aware of Venomous dorsal spines; handle with extreme caution
Appearance and Colouration
The Weedy Scorpionfish is one of the most visually unique species due to its highly elaborate frilly appendages and cryptic colour variations.
• Body Colouration
Can range from purple, red, pink, orange, yellow, brown, or green, often mimicking the surrounding coral and algae.
• Markings
The highly developed frilly appendages create a lace-like appearance, helping the fish remain nearly invisible in its habitat.
• Fins
Large fan-like pectoral fins allow for a slow, walking motion, rather than typical swimming.
Natural Habitat and Behaviour
In the wild, Rhinopias frondosa inhabits rocky reefs, coral rubble, and sandy bottoms, often at depths of 10 to 200 metres.
• Ambush Predator
• Remains motionless for extended periods, waiting for unsuspecting prey.
• Strikes with lightning-fast mouth expansion, creating a vacuum to suck in prey.
• Slow Movement
• Moves in a stalking manner, “walking” along the substrate using its pectoral fins.
• Territorial and Solitary
• Prefers living alone, defending small home territories.
Tank Requirements and Water Parameters
• Minimum Tank Size 250 litres (65 gallons)
• Water Parameters
• Temperature 24°C – 28°C (75°F – 82°F)
• pH 8.1 – 8.4
• Specific Gravity 1.020 – 1.025
• Aquascaping
• Provide caves, overhangs, and coral rubble for hiding.
• Use live rock and fine sand for a natural look.
• Lighting
• Moderate to low, to reduce stress and maintain camouflage.
• Water Movement
• Gentle to moderate, replicating slow reef currents.
Diet and Feeding
The Weedy Scorpionfish is a carnivorous ambush predator, requiring live or frozen meaty foods.
• Primary Diet
• Live mysis shrimp, amphipods, and small marine fish.
• Frozen silversides, squid, and krill once trained.
• Feeding Frequency
3–4 times per week, offering controlled portions.
Feeding Tip:
• If reluctant to eat frozen food, use feeding tongs to mimic prey movement.
Compatibility and Social Structure
• Temperament
• Solitary and territorial, best kept alone or with larger, non-aggressive tank mates.
• Tolerates larger, peaceful fish that will not outcompete it for food.
• Tank Mates
• Suitable with tangs, larger angelfish, and peaceful triggerfish.
• Avoid small fish and shrimp, as they will be eaten.
• Do not house with aggressive predators that may harass it.
Important Considerations
• Venomous Spines
• The dorsal fin spines contain venom, which can cause severe pain and swelling.
• If stung, immerse the affected area in hot water and seek medical attention.
• Feeding Challenges
• May require live food initially, transitioning to frozen over time.
• Reef Compatibility
• While safe for corals, it will prey on ornamental shrimp and small fish.
Summary
The Weedy Scorpionfish (Rhinopias frondosa) is a highly specialised ambush predator, admired for its intricate camouflage and slow, stalking movements. It requires careful handling, a dedicated feeding plan, and a species-appropriate tank setup. Best suited for experienced reef keepers, this species can become an extraordinary centrepiece in a well-maintained aquarium.