Pygmy Scorpionfish (Scorpaenodes scaber)
The Pygmy Scorpionfish (Scorpaenodes scaber), also known as the Pygmy Rockcod, is a cryptic and venomous species belonging to the Scorpaenidae family. Found in shallow rocky and coral reef habitats, this species relies on its camouflage and ambush-hunting strategy to capture small prey. Though rarely seen in the aquarium trade, it is an intriguing species for those fascinated by scorpionfish.
Key Information
• Small fish safe ⚠️ With caution (may prey on very small fish)
• Small invertebrate safe ⚠️ With caution (may consume small crustaceans)
• Coral safe ✅ Yes (does not harm corals)
• Minimum tank size 115 litres (30 gallons)
• Adult size Up to 12 cm (4.7 inches)
• Diet Carnivorous, feeding on small fish and invertebrates
• Be aware of Venomous dorsal spines; handle with extreme caution
Appearance and Colouration
The Pygmy Scorpionfish is well-camouflaged to blend into its surroundings:
• Body Colouration
Typically reddish-brown to mottled tan, allowing it to blend into rocky and coral substrates.
• Markings
Unlike Scorpaenodes evides, this species lacks a distinct dark spot on the gill cover.
• Head Features
Small skin flaps and ridges above the eyes and body break up its outline, enhancing its camouflage.
• Fins
Pectoral fins are broad and translucent, aiding in stability on the seafloor.
Natural Habitat and Behaviour
In the wild, Scorpaenodes scaber is found in shallow coastal waters, coral reefs, and rocky outcrops, often hiding among coral rubble and crevices.
• Nocturnal Predator
• Rests motionless during the day under ledges and within rock formations.
• Actively hunts at night, ambushing small fish and crustaceans.
• Ambush Strategy
• Relies on patience and camouflage, striking prey with rapid mouth expansion.
• Territorial Nature
• Solitary, with a small home range around its hiding spot.
Tank Requirements and Water Parameters
• Minimum Tank Size 115 litres (30 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 rock caves, coral rubble, and overhangs for hiding.
• Use low-light areas to mimic its natural habitat.
• Lighting
• Moderate to low to accommodate its nocturnal behaviour.
• Water Movement
• Moderate, ensuring gentle flow to replicate natural reef conditions.
Diet and Feeding
The Pygmy Scorpionfish is a carnivorous ambush predator, requiring a diet of 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, providing food in 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 similar-sized species.
• Tolerates larger, non-aggressive fish.
• Tank Mates
• Suitable with tangs, larger wrasses, and peaceful angelfish.
• Avoid small fish and shrimp, as they will be eaten.
• Do not house with aggressive predators that may stress or outcompete 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 at first, transitioning to frozen over time.
• Reef Compatibility
• While safe for corals, it will prey on ornamental shrimp and small fish.
Summary
The Pygmy Scorpionfish (Scorpaenodes scaber) is a well-camouflaged ambush predator suited for experienced reef keepers. Its nocturnal habits, cryptic appearance, and venomous spines make it an intriguing but challengingspecies to maintain. With the right environment and careful handling, it can thrive in a marine aquarium, adding an element of natural reef ecology and stealth predation.