Lawnmower Blenny

Geographic Origin and Biotope: Indo-Pacific, from the Red Sea to the Great Barrier Reef. Inhabits the benthic zones of lagoons, pebbly bottoms, seagrass beds and coral reefs exposed to direct light, where algae proliferate.

Taxonomy and Morphology: Lawnmower Blenny (Salarias fasciatus). Blenny. Stocky and elongated body, without scales. Possesses a huge mouth equipped with scraping lips, protruding periscope eyes and feathered "eyebrows" (cirri).

Social Behavior: Funny and Territorial Observer. Does not swim in the water column; moves by "hopping" and resting on rocks or corals using its pectoral fins as arms. Looks at the aquarist with grotesque expressions, moving its eyes independently.

Coloration and Sexual Dimorphism: Perfect Camouflage. Olive-gray or beige background color, studded with jagged vertical bands (fasciatus) in brown, white and green, making it invisible on live rocks. No visible dimorphism, except slightly rounder females.

Aquarium Setup: Mature Reef (Minimum 100 cm / 40 inches). ABSOLUTELY needs an immense rockwork (Live rock) mature for months and widely covered with green microalgae and diatoms. Highly oxygenated water.

Diet and Feeding: The Herbivore par excellence (Lawnmower). Leaves characteristic "kiss marks" on glass and rocks while scraping algae. Huge problem: often refuses dry food. If the tank runs out of filamentous algae and you do not immediately accustom it to Nori seaweed, it will starve to death.

Water Quality: Extremely tolerant. Its thick mucus layer protects it well from ich and skin bacterial infections. Tolerates slight salinity fluctuations, but demands well-oxygenated water due to its passive swimming.

Compatibility and Tankmates: The enemy of other Blennies. It is perfectly Reef Safe (ignores corals and column fish). However, it possesses an atavistic hatred for anyone who looks like it: it will brutally kill any other Salarias or torpedo-shaped fish (Gobies) that approach "its" rocks.

Aquarium Reproduction: Egg layers. Like other blennies, they lay masses of sticky eggs in rocky crevices (or empty shells). The male fanatically guards the nest until hatching. Very small pelagic larvae, almost impossible to raise at home.

Risks and Diseases: Death by Starvation (Sunken Belly). The beginner's mistake: buying the Salarias to clean a newly started aquarium with 2 algae-covered rocks. Once the job is done in 2 days, the fish refuses feeds, its belly horribly caves in like an inverted U and it dies in a month.