How long do Lawnmower Blennies live?
Lawnmower Blennies live about 2-4 years with good care. A tank with steady algae or supplemented greens is what sustains them.
What do Lawnmower Blennies eat?
They graze algae constantly and need nori, spirulina and algae wafers when natural growth runs low. The mistake is assuming they live on glass algae alone — supplement or they starve after a cleanup.
Tank size and water parameters
A 30-gallon (115 L) tank suits one. Target 72-80°F (22-27°C), pH 8.1-8.4, specific gravity 1.020-1.025, ammonia/nitrite zero, nitrate under ~20 ppm. Provide live rock with algae and a cave.
Common mistakes with Lawnmower Blennies
Key errors: a sterile new tank with no algae (they starve); no supplement after cleanup; an open tank (they perch and jump); and two blennies fighting in a small space.
Beginner mistakes to avoid
- No algae or supplement — they starve once tank algae is gone.
- Brand-new sterile tank — they need established algae growth.
- Open tank — they perch and can jump; cover it.
- Two blennies — they fight; keep one per tank.