Lawnmower Blenny

Lawnmower blenny, a notable marine aquarium species, gets its name because of its trait of consuming or mowing down algae growing at the bottom of the rocks or glasses in the aquarium. Its mottled pattern, bulging eyes, and slender body make it an immensely attractive aquarium fish, besides being popular among those keen to control their tank’s algae growth.

Quick Information

Scientific Name	Salarias fasciatus
Other Names	Jewelled blenny, jeweled rockskipper, rock blenny, algae blenny
Origin	Indo-Pacific belt stretching from the Red Sea and East African region to the Samoan and Micronesian Islands
Type	Saltwater fish
Conservation Status	Least Concern (by the IUCN)
Behavioral Characteristics	Calm, peaceful, and curious about its environment, but could get aggressive with other lawnmower blennies  (of the same sex) or similar-looking species
School Size	Mostly kept singly, in pairs, or small schools of 3 – 4 fishes
Physical Traits	Elongated, slender body like snakes or eels; small head with whisker-like projections on it; smooth lip margins; large bulging eyes; a single dorsal fin, and a big mouth
Scales	Usually absent, but might be present in some
Colors	Olive or brown body with dark-colored bars  and elongated or round white spots of various sizes
Size (How big do they get)	Small; 5 inches (13 cm)
Lifespan (How long do they live)	2 – 4 years
Sexual Dimorphism	Present, but difficult to identify: Males are bigger with larger anal fins than their female counterparts
Probable Diseases	White spot disease, ich, bloating (especially when overfed)
Approximate Price	$25 – 40

Tank Setup & Care Sheet Details

Care Level	Beginner
Tank Size	30 gallons (113.5 liters) for single fish; 50 gallons (189 liters) for pairs; a bigger tank for keeping more individuals

Water Parameters

pH Level	8.0-8.4
Temperature	72 – 78°F (22.2 – 25.5°C)
Hardness	8 – 12 dGH
Salinity	1.020 – 1.025
Aquarium  Water Flow	Moderate to high

Tank Ambience

Lighting	Moderate (cannot withstand bright lights)
Substrate Type	Live rock and sand
Tank Mates	Compatible with: Other lawnmower blennies if dwelling together as a mated pair,  pistol shrimp, scooter blenny, and species that are less aggressive and not of a similar color or pattern as theirs Incompatible with: Same-sex lawnmower blennies (aggression, mainly seen in males), starry blenny  and tailspot blenny(since both are  prominent algae eaters) diamond goby, dartfish,  pipefish, and seahorses
Suitable Position in the Tank	Middle

Feeding

Diet (What do they eat)	Algae (filamentous microalgae, green hair algae, foraminiferans); spirulina; seaweed; fish eggs; small snails; corals as well as other invertebrates; chopped vegetables like spinach and lettuce may also be given
Frequency	2 – 3 times a day

Important Things to Know for Fish Keepers

• Despite their small size, this fish needs big tanks to promote sufficient algae growth and also to have enough space for swimming.  
• In case there is an insufficient amount of algae growth in your tank, opt for algae wafers or pellets as an alternate source. You can even place nori in between the live rock as a substitute.
• Some owners have noticed heavy breathing and panting in their lawnmower blenny, which is often considered normal if the fish is healthy and eating well.  A combination of other signs like restlessness and low appetite would call for a fish veterinarian’s consultation. 

FAQs