Black Triggerfish (Melichthys niger)
• Small fish safe: ⚠️ With caution (generally peaceful but may eat very small fish)
• Small invert safe: ❌ No (will prey on small crustaceans and mollusks)
• Coral safe: ⚠️ With caution (less destructive than other triggers but may nip at corals)
• Minimum tank size: 380 liters (100 gallons) for juveniles, 570+ liters (150+ gallons) for adults
• Adult size: Up to 50 cm (20 inches)
• Diet: Omnivorous, feeding on plankton, small invertebrates, and algae
• Be aware of: One of the more peaceful triggerfish; requires open swimming space; may rearrange rockwork
Appearance and Coloration
The Black Triggerfish, also known as the Durgeon Triggerfish, is a sleek, deep-colored fish with an iridescent black to dark green body, which may shimmer with blue and purple hues under aquarium lighting. Its fins are highlighted with a bright blue outline, adding to its elegant and mysterious appearance.
Despite its dark coloration, the Black Triggerfish stands out in an aquarium due to its bold personality and constant movement.
Natural Habitat and Behavior
Native to the Indo-Pacific and Eastern Pacific Oceans, Melichthys niger inhabits outer reef slopes, lagoons, and deep coastal waters, often swimming in the water column rather than near the substrate. It is found at depths ranging from 5 to 75 meters (16 to 250 feet).
Unlike more aggressive triggerfish, the Black Triggerfish is primarily a planktivore, meaning it feeds in the open water rather than hunting benthic prey. This reduces aggression compared to other triggers that actively hunt crustaceans on the reef. However, as with all triggers, it can become territorial, especially as it matures.
Tank Requirements and Water Parameters
• Minimum Tank Size: 100 gallons (380 liters) for juveniles, 150+ gallons (570+ liters) for adults
• Water Parameters:
• Temperature: 24°C – 27°C (75°F – 81°F)
• pH: 8.1 – 8.4
• Specific Gravity: 1.020 – 1.025
• Aquascaping:
• Provide open swimming areas as this species is highly active.
• Secure rockwork and caves for resting and shelter.
• Avoid loose decorations, as Black Triggers may move objects in the tank.
• Lighting: Moderate to bright reef lighting.
• Water Movement: Moderate to strong, simulating reef currents.
Diet and Feeding
Black Triggerfish are omnivores, meaning they require a balanced diet of meaty foods and plant matter. Their planktivorous tendencies make them easier to feed compared to more aggressive trigger species.
• Natural Diet: Plankton, small crustaceans, mollusks, and marine algae.
• Captive Diet:
• Mysis and brine shrimp.
• Chopped seafood (shrimp, squid, clams).
• High-quality marine pellets and flakes.
• Nori or other algae-based foods to support overall health.
Feeding Frequency: 1-2 times per day to maintain energy levels and coloration.
Compatibility and Social Structure
• Temperament:
• One of the more peaceful triggerfish, but still semi-aggressive.
• Less likely to attack tank mates but may become territorial in smaller tanks.
• Tank Mates:
• Compatible with other semi-aggressive fish, such as:
• Tangs
• Large angelfish
• Puffers
• Other moderately aggressive triggers (in large tanks)
• Avoid housing with small ornamental shrimp or tiny fish, as they may be seen as prey.
• Not suitable for nano or peaceful community tanks.
• Reef Compatibility: ⚠️ With caution—less destructive than other triggers but may nibble on corals and invertebrates.
Important Considerations
• Can Be Territorial: Though more peaceful than most triggers, it may still defend its space in smaller tanks.
• May Rearrange Rockwork: Like all triggerfish, it moves objects in the tank, so ensure decorations are secure.
• Growth Rate: Can grow fairly quickly, requiring a large tank to accommodate its active swimming behavior.
• More Peaceful Option: If looking for a triggerfish that isn’t overly aggressive, this species is one of the best choices.