Niger Triggerfish (Odonus niger)
• Small fish safe: ❌ No (may eat small fish when mature)
• Small invert safe: ❌ No (will prey on crustaceans and small invertebrates)
• Coral safe: ⚠️ With caution (may nip at corals and rearrange rockwork)
• Minimum tank size: 380 liters (100 gallons)
• Adult size: Up to 50 cm (20 inches)
• Diet: Omnivorous, feeding on plankton, small invertebrates, and meaty foods
• Be aware of: Can become aggressive as it matures; requires ample swimming space; may reconfigure rockwork
Appearance and Coloration
The Niger Triggerfish is a striking deep-blue to purple fish with iridescent highlights that can shift in hue depending on lighting and mood. Its elongated dorsal and anal fins create a distinctive, crescent-shaped tail with a green or red tinge. This gives it a graceful yet powerful swimming motion, making it one of the more elegant triggerfish in the hobby.
A unique feature of the Niger Trigger is its jaw structure and constantly moving teeth, which are well-adapted for breaking down hard-shelled invertebrates.
Natural Habitat and Behavior
Native to the Indo-Pacific region, Odonus niger is commonly found in deep reef slopes and lagoons at depths of 5 to 35 meters (16 to 115 feet). Unlike many other triggerfish, the Niger Trigger is primarily a planktivore, feeding mid-water on zooplankton rather than actively hunting on the substrate.
Despite its more peaceful reputation compared to other triggers, it can still exhibit territorial tendencies, especially as it matures. In the wild, Niger Triggerfish are often seen swimming in the water column, unlike benthic species that spend more time near the substrate.
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 large open swimming areas to accommodate its active swimming behavior.
• Secure rock structures to prevent them from being knocked over.
• Caves or overhangs for the fish to retreat into at night.
• Lighting: Moderate to bright reef lighting.
• Water Movement: Moderate to strong flow, simulating reef currents.
Diet and Feeding
Niger Triggerfish are omnivores with a preference for meaty foods and planktonic organisms. While less destructive than some other triggers, they will opportunistically hunt small invertebrates.
• Natural Diet: Zooplankton, small crustaceans, and marine algae.
• Captive Diet:
• Mysis and brine shrimp.
• Chopped seafood (shrimp, squid, clams).
• High-quality marine pellets and flakes.
• Occasional vegetable matter (such as nori or algae-based foods).
Feeding Frequency: 1-2 times per day to maintain energy levels and coloration.
Compatibility and Social Structure
• Temperament:
• More peaceful than other triggerfish, but still semi-aggressive, especially as it matures.
• May tolerate tank mates when young but can become territorial in smaller tanks.
• Tank Mates:
• Compatible with other larger semi-aggressive fish, such as:
• Tangs
• Large angelfish
• Puffers
• Groupers
• Not suitable for nano or peaceful community tanks.
• Caution is advised with slow-moving fish, as triggers can be fin nippers.
• Reef Compatibility: ⚠️ With caution—may leave corals alone but will likely eat small invertebrates like shrimp and crabs.
Important Considerations
• Can Be Territorial: While one of the less aggressive triggers, it can still become dominant, particularly in smaller tanks.
• May Rearrange Rockwork: Like other triggerfish, Niger Triggers often move objects around their environment.
• Jaw Strength: Requires hard-shelled foods (like mussels or clams) to keep its teeth worn down naturally.
• Growth Rate: Juveniles start small but can grow rapidly, requiring a large tank as they mature.
The Niger Triggerfish is one of the most reef-compatible and mild-mannered triggerfish, but still requires a large, well-planned tank with robust tank mates.