Purple Firefish (Nemateleotris decora)
• Small fish safe: ✅ Yes
• Small invert safe: ✅ Yes
• Coral safe: ✅ Yes
• Minimum tank size: 75 liters (20 gallons)
• Adult size: Up to 9 cm (3.5 inches)
• Diet: Carnivorous, primarily feeding on zooplankton
• Be aware of: Prone to jumping, requiring a secure lid; can be territorial toward conspecifics in smaller tanks; needs hiding spots for security
Appearance and Coloration
The Purple Firefish is a beautifully colored, elongated goby with a lavender-to-white front half that fades into a deep purple toward the tail. Its dorsal fin is long and often raised when alert, giving it a dramatic and elegant appearance. Its striking coloration and graceful swimming make it a standout species in any reef aquarium.
Natural Habitat and Behaviour
Nemateleotris decora inhabits deep reef slopes and outer reef drop-offs, typically at depths of 25 to 70 meters (80 to 230 feet). They are often seen hovering above the substrate, retreating into rock crevices when threatened. This species tends to be slightly more reclusive than Nemateleotris magnifica, benefiting from a peaceful tank with plenty of rockwork for shelter.
Tank Requirements and Water Parameters
• Minimum Tank Size: 20 gallons (75 liters) for a single fish; larger tanks required for pairs or groups.
• Water Parameters:
• Temperature: 24°C – 27°C (75°F – 81°F)
• pH: 8.1 – 8.4
• Specific Gravity: 1.020 – 1.025
• Aquascaping: Provide live rock structures with caves and overhangs for hiding while allowing open space for swimming.
• Lighting: Moderate to bright lighting, mimicking their natural reef environment.
• Water Movement: Moderate flow is ideal.
• Tank Cover: A tight-fitting lid is essential, as they are known to jump when startled.
Diet and Feeding
Purple Firefish are micro-carnivores, feeding primarily on planktonic organisms in the wild:
• Natural Diet: Zooplankton and small invertebrates.
• Captive Diet:
- Mysis shrimp
- Brine shrimp
- Copepods
- Finely chopped seafood (fish, shrimp)
- High-quality marine flakes and pellets
Feed small portions 2-3 times per day to keep them well-fed and active.
Compatibility and Social Structure
- Temperament:
Peaceful but territorial toward conspecifics if housed in a small tank.
Can be kept in mated pairs or small groups in larger tanks with sufficient rock structures for hiding.
- Tank Mates:
Peaceful community fish like gobies, small wrasses, and clownfish.
Avoid aggressive tank mates like large angelfish, triggerfish, or dottybacks that may stress or outcompete them.
- Reef Compatibility: 100% reef-safe and will not bother corals or invertebrates.
Important Considerations
• Jumping Behavior: Extremely prone to jumping, so a covered tank is required.
• Shy at First: Can be reclusive when newly introduced but will become bolder over time.
• Tank Stability: Prefers stable, mature aquariums with minimal fluctuations in water quality.