Lawnmower Blenny (Salarias fasciatus)

The Lawnmower Blenny (Salarias fasciatus) is one of the most useful and entertaining fish you can add to a saltwater tank. This beginner-friendly, peaceful algae grazer spends its day hopping from rock to rock, mowing nuisance film and hair algae off live rock and glass. With big expressive eyes, a mottled camouflage pattern, and curious perching habits, it has loads of personality while earning its keep as a natural part of your cleanup crew.

Pair it with the rest of our saltwater livestock and marine fish to round out a reef or FOWLR system.

Care Guide

The Lawnmower Blenny is hardy and easy to keep, which makes it a great first algae-eater for a maturing aquarium. It does best in an established tank with plenty of live rock and natural algae growth to graze on. Give it open rockwork with caves and ledges where it can perch and retreat. Once it has grazed the available algae down, supplement its diet so it never goes hungry (see Recommended Foods below).

• Tank size: 30 gallon minimum, 40 gallons or larger preferred for a steady algae supply
• Aquascape: Mature live rock for grazing, plus caves and ledges to perch and hide
• Water flow: Low to moderate; it likes to perch in a gentle current
• Lid: Recommended, as startled blennies can jump
• Acclimation: Drip acclimate slowly, this species dislikes sudden parameter swings

Specifications

Compatibility

The Lawnmower Blenny is peaceful toward dissimilar tank mates but territorial toward other blennies and fish of similar shape, especially in smaller tanks. Keep only one per aquarium unless you have a confirmed mated pair in a large system. It is reef safe with most corals, though a hungry blenny may occasionally nip at SPS or clam mantles if algae runs scarce, so keep it well fed.

Good tank mates: clownfish, cardinalfish, firefish, tangs, wrasses, and reef-safe cleanup crew like the Scarlet Skunk Cleaner Shrimp, turbo snails, and hermit crabs.

Avoid: other blennies, mandarin gobies and similar-shaped grazers, and aggressive fish that will outcompete it for perching and grazing spots.

Recommended Foods & Supplies

• BRS Nori Seaweed Sheets on a Sea Veggies veggie clip for daily grazing
• Seachem NutriDiet Herbivore Tabs and Vitalis Marine Pellets for supplemental nutrition
• Spirulina powder to boost algae-based feeds
• A quality salt mix and water care for a stable, algae-friendly tank
• Browse our full fish food selection

Frequently Asked Questions

Will a Lawnmower Blenny clear all my algae?
It is excellent at film and hair algae on rock and glass, but it will not eat bubble algae or cyanobacteria. Once it grazes the tank down, supplement with dried seaweed and herbivore foods so it stays well fed.

Is it reef safe?
Yes, it is considered reef safe. On rare occasions a hungry blenny may pick at SPS polyps or clam mantles, so keep algae and supplemental food available.

How many can I keep together?
One per tank is the rule unless you have a large system and a confirmed mated pair. Two unpaired blennies will usually fight.

What size tank does it need?
A well-established 30 gallon tank is the minimum, but 40 gallons or larger gives it more grazing surface and is easier to keep stocked with algae.