Algae Blenny - Salarias fasciatus

Algae Blenny (Salarias fasciatus)

The Algae Blenny, Salarias fasciatus, is a hardy, characterful and highly useful marine blenny, best known for its algae-grazing behaviour, comical expression and watchful perching habits. Also commonly known as the Lawnmower Blenny, Jewelled Blenny or Rockskipper Blenny, this species is a popular choice for mature marine aquariums where it can help graze algae films from rockwork and surfaces. It is generally peaceful, reef safe and full of personality, but it should be kept in an established aquarium with enough natural grazing and suitable supplementary foods.

Common Name:
Algae Blenny, Lawnmower Blenny, Jewelled Blenny, Jeweled Blenny, Rockskipper Blenny, Sailfin Blenny.

Scientific Name (Latin):
Salarias fasciatus

Maximum Size:
Up to around 14 cm, though many aquarium specimens are usually closer to 10–12 cm.

Water Type:
Marine

Origin / Natural Habitat:
Found widely across the Indo-Pacific, including the Red Sea, East Africa, Indian Ocean, Indonesia, southern Japan, Australia, New Caledonia, Samoa and surrounding tropical reef regions. In the wild, Algae Blennies inhabit reef flats, shallow lagoons, seaward reefs, rubble zones and algae-rich rocky areas. They are usually seen resting on rockwork or coral outcrops, scraping algae and detrital growths from hard surfaces throughout the day.

Water Parameters:
Temperature: 24–27°C
pH Range: 8.1–8.4
Hardness or Salinity: SG 1.020–1.025

Temperament:
Peaceful to mildly territorial. Algae Blennies are usually safe with most peaceful and moderately active marine fish, but they may become territorial towards similar-shaped blennies, gobies or other algae-grazing fish, especially in smaller aquariums. Best kept as a single specimen unless the aquarium is very large and compatibility has been carefully planned.

Diet:
Herbivorous grazer with detritus-feeding tendencies. In the wild, this species scrapes algae, biofilm and detrital material from reef surfaces. In the aquarium, it should have access to mature live rock with natural algae growth, but this should be supported with suitable foods such as marine algae sheets, nori, spirulina flakes, herbivore pellets, algae wafers, vegetable-based frozen foods and occasional finely chopped marine foods. It should not be added to a very clean or newly set up aquarium with no grazing available.

Minimum Tank Size:
A practical minimum of around 150–200 litres is recommended for a single specimen, with larger aquariums preferred for long-term success. Provide mature rockwork, grazing surfaces, caves, ledges and stable water quality.

Behaviour & Activity:
A characterful perching blenny that spends much of its time resting on rockwork, watching the aquarium and hopping between surfaces. It uses comb-like teeth to rasp at algae films and biofilm, often leaving visible grazing marks on glass, rock and equipment. Algae Blennies are not constant open-water swimmers, but they are active grazers and need plenty of established surfaces to explore. A secure lid is recommended, as blennies can jump when startled.

Reef Safe:
Reef Safe
Algae Blennies are considered reef safe and do not normally nip corals, clam mantles or sessile invertebrates. They are a useful addition to mature reef aquariums and can help with some algae growth, although they should not be relied upon as the only algae-control method. Very hungry individuals may occasionally graze close to coral bases or irritate delicate corals while feeding, but this is usually behaviour-related rather than direct coral predation.

Special Requirements or Care Notes:
Best kept in a mature aquarium with established algae and biofilm growth. Avoid adding to sterile new systems or aquariums where all natural algae has been removed, as underfed specimens can lose condition. Supplement feeding regularly, especially once visible algae levels are reduced. This species can become thin if it does not accept prepared foods, so body shape and belly condition should be monitored. Avoid keeping with aggressive tank mates or very similar algae blennies unless the aquarium is large enough to provide separate territories.

Suitable for:
Beginner to Intermediate fishkeepers

Availability:
Common in trade / Availability can vary depending on size, supplier and import season

All images are a visual representation of the fish you will receive, made to be as accurate as possible. Please note that Mother Nature is a wonderful thing, and variation in patterns and colours will occur — that is part of the unique beauty of these animals.