Lined Blenny (Ecsenius lineatus)

The Lined Blenny is a compact, understated little fish that earns a place in the reef through sheer personality and utility rather than flashy colour. The lower half of the body is white and the upper half is brown to black in coloration, and their very large eyes and small mouth give these fish a genuinely comical look that wins over anyone who takes a moment to watch one perching in the rockwork. Colour and patterning can vary by region and maturity, with some individuals showing a more broken pattern of vertical bars or blotches alongside or instead of the classic lateral line. Like all Ecsenius blennies, this species is an active grazer, a dedicated rockwork percher, and a fish with a bigger personality than its size suggests.

Why we love it

• Distinctively patterned with bold two-tone colouring and oversized, expressive eyes
• Hardy, easy to keep, and adaptable to a wide range of peaceful reef systems
• Constant daytime grazer that actively helps manage nuisance algae on rockwork
• Peaceful species that will generally mind its own business while enjoying watching current events from a favourite perch among coral or live rock
• Compact size makes it suitable for smaller systems where larger blennies would not fit

Suggested parameters

• Temperature: 24 to 26°C (75 to 79°F)
• Salinity: 1.025 to 1.026 SG
• pH: 8.1 to 8.4
• Alkalinity: 8 to 10 dKH
• Calcium: 400 to 450 ppm
• Magnesium: 1250 to 1400 ppm
• Nitrate: 5 to 20 ppm
• Phosphate: 0.03 to 0.12 ppm

Care and temperament

• Difficulty: Easy
• Temperament: Peaceful; may defend a small territory around its preferred perch or crevice
• Reef safe: Yes, with the note that this blenny may nip at the polyps and base of Acropora and Montipora and is not well suited for SPS-dominant tanks with immature or small colonies
• Minimum tank size: 30 gallons with plenty of live rock for perching, grazing, and hiding
• Can be maintained in reef or fish-only aquariums with rocky areas containing caves and holes, and ideally heavy algae growth on the rockwork to graze on
• A tight-fitting lid is essential; this species is a capable jumper

Diet

The Lined Blenny is a dedicated herbivore and needs consistent access to algae to stay healthy.

• Grazes naturally on algae growing on live rock and tank surfaces throughout the day
• Nori and dried seaweed sheets on a clip
• Spirulina-based pellets and flakes
• Frozen herbivore blends containing marine and blue-green algae
• If sufficient aquarium algae is not present, the diet must be supplemented with vegetable matter and spirulina-based foods; without enough greens this fish will slowly waste away
• Spirulina-based foods treated with Selcon offer additional nutritional benefits
• Feed twice daily, offering only what the fish will consume within a few minutes

Compatibility and tankmates

• Excellent with clownfish, small wrasses, peaceful gobies, shrimp gobies, dartfish, and most reef community fish
• Tankmates must be peaceful, as even moderately aggressive species will prevent this fish from getting its share of food
• Keep one per system unless a confirmed mated pair
• Will coexist with many heterospecific tankmates as long as they do not have a similar body shape or are not overly aggressive
• Generally safe with most invertebrates, though caution is warranted with very small ornamental crustaceans

Health and acclimation notes

The Lined Blenny is a hardy and forgiving species that settles quickly into a well-established system with mature live rock and a functioning algae crop. A drip acclimation of at least 30 minutes is recommended. Care requirements centre on a stable, peaceful environment with ample rocky structure for perching and hiding and a diet consistently high in vegetable matter. A well-fed Lined Blenny in a system with enough territory is one of the most reliable and trouble-free fish in the hobby.

What you are buying

• You will receive: 1 Lined Blenny (Ecsenius lineatus)
• Colour and patterning can vary between individuals and regions; some specimens display more distinct lateral striping while others show a more mottled or barred pattern

Slow acclimation is recommended. A tight-fitting lid is essential, as this species will jump.