Blue Gudgeon Dartfish (Ptereleotris heteroptera)

 

• Small fish safe: ✅ Yes

• Small invert safe: ✅ Yes

• Coral safe: ✅ Yes

• Minimum tank size: 114 liters (30 gallons)

• Adult size: Up to 12.7 cm (5 inches)

• Diet: Carnivorous, primarily feeding on zooplankton

• Be aware of: Prone to jumping, requiring a secure lid; best kept in pairs or small groups; requires ample hiding spots to feel secure

 

Appearance and Coloration

The Blue Gudgeon Dartfish, also known as the Blacktail Goby or Blacktail Dartfish, features a slender, elongated body with a pale blue to greenish hue. A distinctive black spot adorns the base of its tail fin, providing a striking contrast to its overall coloration. This species’ graceful swimming and vibrant appearance make it a captivating addition to marine aquariums.

 

Natural Habitat and Behavior

Ptereleotris heteroptera is native to the Indo-Pacific region, including areas such as Fiji and Indonesia. In the wild, these fish inhabit reef environments, often found hovering above sandy substrates or coral rubble. They are social creatures, typically forming small groups, and are known for their peaceful demeanor. However, they can be shy, especially when first introduced to a new environment. Providing ample hiding spots and keeping them in pairs or small groups can help reduce stress and encourage natural behaviors.

 

Tank Requirements and Water Parameters

• Minimum Tank Size: 30 gallons (114 liters)

• Water Parameters:

• Temperature: 22°C – 25.5°C (72°F – 78°F)

• pH: 8.1 – 8.4

• Specific Gravity: 1.020 – 1.025

• Aquascaping: Incorporate plenty of live rock to create caves and crevices, providing necessary hiding spots. Ensure open swimming areas to accommodate their active nature.

• Lighting: Moderate to bright lighting, simulating their natural reef environment.

• Water Movement: Moderate flow to replicate their natural habitat.

• Tank Cover: A secure, tight-fitting lid is essential, as Blue Gudgeon Dartfish are known to jump, especially when startled.

 

Diet and Feeding

In their natural habitat, Blue Gudgeon Dartfish primarily consume zooplankton and small invertebrates. In captivity, they adapt well to a varied diet:

• Captive Diet:

• Mysis shrimp

• Brine shrimp

• Copepods

• Finely chopped seafood (e.g., fish, shrimp)

• High-quality marine flakes and pellets

Feeding small portions 2-3 times daily helps maintain their health and vibrant coloration. Due to their limited fat reserves, it’s crucial to ensure they begin eating promptly during acclimation and continue to receive frequent feedings. 

 

Compatibility and Social Structure

• Temperament: Generally peaceful; they thrive when kept in pairs or small groups.

• Tank Mates: Compatible with other peaceful species such as gobies, clownfish, and small wrasses. Avoid housing with aggressive or significantly larger species that may cause stress or outcompete them for food.

• Reef Compatibility: 100% reef-safe; they do not harm corals or invertebrates.

 

Important Considerations

• Jumping Behavior: Due to their propensity to jump, especially when startled, a securely covered aquarium is mandatory.

• Shyness: May exhibit timid behavior upon introduction to a new environment. Providing ample hiding spots will help them acclimate and reduce stress.

• Tank Stability: Prefers established aquariums with stable water parameters to thrive.