Lawnmower Blenny 

Also known as Jeweled Blenny, Sailfin Blenny

The Lawnmower Blenny is one of the most popular and effective algae-grazing fish in the marine aquarium hobby. With its intricate spotted pattern and perpetually active grazing behavior, this hardy blenny is both functional and entertaining, earning its common name from its tireless algae-eating habits.

Key Features

• Scientific Name: Salarias fasciatus
• Common Names: Lawnmower Blenny, Jeweled Blenny, Sailfin Blenny
• Adult Size: Up to 5 inches
• Lifespan: 4-6 years with proper care
• Temperament: Peaceful but territorial toward other blennies and similar fish
• Reef Compatibility: Completely reef safe; will not harm corals or invertebrates
• Minimum Tank Size: 30 gallons minimum; 40+ gallons preferred
• Experience Level: Beginner; extremely hardy and easy to care for

Habitat & Tank Requirements

• Tank Environment: Provide extensive live rock with caves, crevices, and flat grazing surfaces. This blenny spends most of its time grazing algae from rocks. Requires established tanks with mature algae growth for long-term success.
• Water Parameters:
  • Temperature: 72-78°F (22-26°C)
  • Salinity: 1.020-1.025
  • pH: 8.1-8.4
  • Very adaptable to typical reef conditions
• Equipment Recommendations:
  • Standard filtration system
  • Protein skimmer
  • Moderate water circulation These maintain healthy conditions for this resilient species.

Diet & Feeding

Lawnmower Blennies are primarily herbivorous grazers. Recommended foods include:

• Staples: Herbivore pellets, spirulina flakes, algae-based foods
• Plant Matter: Nori seaweed, marine algae sheets, spirulina (essential)
• Frozen Foods: Herbivore preparations with spirulina and marine algae
• Natural Grazing: Film algae, hair algae, diatoms from live rock and glass (primary food source)
• Feeding Frequency: Supplemental feeding once daily; continuous grazing throughout the day
• Special Note: MUST have constant access to algae; supplement with prepared algae if natural growth is insufficient

Notes & Considerations

• One of the best algae control fish available; extremely effective at managing film algae, hair algae, and diatoms.
• Very hardy and adaptable; excellent choice for beginner reef keepers.
• Extremely personable with entertaining grazing behavior; constantly active during daylight hours.
• Will establish and vigorously defend a territory from other blennies and similar-shaped fish.
• A secure aquarium lid is essential; excellent jumpers.
• Can starve in tanks without sufficient algae growth; must provide supplemental vegetable matter.
• Generally peaceful toward all tankmates except other blennies or gobies.
• May perch on corals but do not damage them.
• Intricate spotted patterns and comical facial expressions make them aquarium favorites.

Why Choose a Quarantined Lawnmower Blenny?

Purchasing a quarantined specimen from us means you’re starting with a healthier, better-acclimated fish. All fish are observed, treated as needed, and conditioned to accept prepared foods before sale, giving you a stronger chance of long-term success with this hardworking and entertaining species.