The Forktail Blenny (Meiacanthus atrodorsalis), also known as the Lyretail Fang Blenny or Yellowtail Fang Blenny, is a vibrant marine fish celebrated for its striking appearance and peaceful demeanor. Native to the Indo-Pacific region, this species is a popular choice among aquarists seeking an active and hardy addition to their marine aquariums.
• 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: Omnivorous, with a preference for zooplankton
• Be aware of: Possesses venomous fangs used for defense; requires ample hiding spots; known to jump, so a secure lid is essential.
Appearance and Coloration
The Forktail Blenny showcases a pale blue body that transitions into a vibrant yellow towards the tail, with a caudal fin resembling a fork due to its two elongated exterior spines. Males are generally larger than females and may exhibit a succession of color changes during breeding. Adults can reach up to 12.7 cm (5 inches) in length.
Natural Habitat and Behavior
In the wild, Meiacanthus atrodorsalis inhabits lagoons and seaward-facing reefs, preferring rocky environments with steep cliffs and drop-offs at depths ranging from 1 to 30 meters. They are known for their active swimming in open water, an unusual trait among blennies, and possess venomous fangs used for defense against predators.
Tank Requirements and Water Parameters
To ensure the well-being of the Forktail Blenny in captivity:
• Minimum Tank Size: A 30-gallon (114 liters) aquarium is recommended to provide sufficient space for swimming and exploration.
• Water Parameters:
• Temperature: 22°C – 27°C (72°F – 80°F)
• pH: 8.1 – 8.4
• Specific Gravity: 1.020 – 1.025
• Aquascaping: Incorporate ample live rock to create hiding spots and grazing surfaces, mimicking their natural reef environment. Ensure there is open space for active swimming.
• Lighting: Moderate to bright lighting supports natural algae growth, supplementing their diet.
• Water Movement: Moderate flow replicates their natural habitat and encourages active behavior.
• Tank Cover: A secure lid is essential, as Forktail Blennies are known to jump, especially when startled.
Diet and Feeding
Forktail Blennies are omnivores with a preference for zooplankton:
• Natural Diet: In their natural habitat, they primarily feed on zooplankton and small invertebrates.
• Captive Diet: Offer a varied diet that includes:
• Finely chopped seafood (e.g., shrimp, squid)
• Mysis shrimp
• Vitamin-enriched brine shrimp
• Frozen herbivore preparations
Feeding small amounts 2-3 times daily is recommended to maintain their energy levels and support healthy growth.
Compatibility and Social Structure
The Forktail Blenny is generally peaceful and suitable for community tanks:
• Temperament: They exhibit a docile nature but may become territorial towards similar species, especially in smaller tanks. It’s advisable to keep only one Forktail Blenny per aquarium unless a mated pair is introduced.
• Tank Mates: Compatible with a variety of non-aggressive fish and invertebrates. Avoid housing with large, aggressive species that may intimidate or outcompete them for resources.
• Reef Compatibility: Considered reef-safe, they do not harm corals or sessile invertebrates.
Important Considerations
• Venomous Fangs: While primarily used for defense, exercise caution during tank maintenance to avoid potential bites.
• Tank Maturity: Introduce them to well-established aquariums with stable water parameters to ensure health and longevity.
• Health Monitoring: Regular observation is necessary to ensure they are receiving adequate nutrition and to detect any signs of stress or disease early.