The Linear Blenny (Ecsenius lineatus), also known as the Lined Blenny or Lined Combtooth Blenny, is a small marine fish appreciated for its distinctive appearance and beneficial algae-grazing habits. Native to the tropical waters of the Indo-West Pacific.
• Small fish safe: ✅ Yes
• Small invert safe: ✅ Yes
• Coral safe: ⚠️ With caution
• Minimum tank size: 114 liters (30 gallons)
• Adult size: Up to 9 cm (3.5 inches)
• Diet: Primarily herbivorous, feeding on algae
• Be aware of: May nip at small-polyp stony (SPS) corals, especially in tanks with immature or small colonies; requires ample hiding spots and live rock for grazing; known to jump, so a secure lid is essential.
Appearance and Coloration
The Linear Blenny features a slender, elongated body with a distinctive coloration pattern. The upper half of its body ranges from brown to black, while the lower half is white. A prominent black stripe runs laterally from the eye to the tail, often bordered by yellow or white edges. This striking contrast, along with its large eyes and small mouth, gives the fish a unique and appealing appearance. Adults typically reach up to 9 cm (3.5 inches) in length.
Natural Habitat and Behaviour
In the wild, Ecsenius lineatus inhabits shallow coral reefs and rocky substrates, often found at depths ranging from 1 to 28 meters. They are benthic dwellers, frequently seen perching on rocks or within crevices. These blennies are known for their peaceful and inquisitive nature, making them active and engaging inhabitants in an aquarium setting.
Tank Requirements and Water Parameters
To ensure the health and well-being of the Linear Blenny in captivity:
• Minimum Tank Size: A 30-gallon (114 liters) aquarium is recommended to provide sufficient space for grazing 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 swimming and perching.
• Lighting: Moderate lighting supports the growth of algae, which constitutes a significant part of their diet.
• Water Movement: Moderate flow replicates their natural habitat and encourages active behavior.
• Tank Cover: A secure lid is essential, as Linear Blennies are known to jump, especially when startled.
Diet and Feeding
Linear Blennies are primarily herbivores with a strong preference for algae:
• Natural Diet: In their natural habitat, they graze on various forms of algae, aiding in controlling algal growth on reefs.
• Captive Diet: To replicate their natural feeding habits, provide a diet that includes:
• Frozen and dried foods containing marine and blue-green algae, such as spirulina.
• Fresh macroalgae or seaweed, like nori sheets, secured within the tank.
• They may also consume naturally occurring algae growing on live rock and tank surfaces, contributing to algae control within the aquarium.
Feeding small amounts 2-3 times daily is recommended to maintain their energy levels and support healthy growth.
Compatibility and Social Structure
The Linear Blenny is generally peaceful and well-suited for community aquariums:
• Temperament: They exhibit a docile nature but may become territorial towards similar species, especially in smaller tanks. It’s advisable to keep only one Linear Blenny per aquarium unless a mated pair is introduced in a sufficiently large system.
• 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: While generally considered reef-safe, caution is advised in tanks dominated by small-polyp stony (SPS) corals. Linear Blennies have been known to nip at the polyps or bases of Acropora and Montipora species, particularly if the aquarium lacks sufficient algae or if coral colonies are small or immature.
Important Considerations
• Coral Interaction: Monitor their behavior around SPS corals, especially in tanks with small or developing colonies, to prevent potential damage.
• Tank Maturity: Introduce them to well-established aquariums with stable water parameters and adequate natural algae growth to support their grazing habits.
• Health Monitoring: Regular observation is necessary to ensure they are receiving adequate nutrition and to detect any signs of stress or disease early.