Lawnmower Blenny

Overview

The Lawnmower Blenny is one of the most popular algae-eating fish in the marine hobby, prized for its ability to graze film algae and hair algae off rock and glass. It has a mottled brown-green body with darker banding and a comical, wide-eyed face that gives it a lot of personality for a relatively small fish.

It's hardy, easy to care for, and does best in a tank with an established algae film already present when it arrives, since this is its primary food source. In algae-poor or newer tanks it needs consistent supplemental feeding to avoid starving.

Its usefulness as a natural algae grazer combined with its easygoing temperament makes it a reliable choice for a very wide range of reef and fish-only setups.

Compatibility

Lawnmower Blennies are peaceful toward other fish and fully reef safe, leaving corals, clams, and invertebrates alone. They can occasionally show mild territorial behaviour toward other blennies of similar shape and colour, particularly in smaller tanks, but rarely cause serious problems.

They mix well with community fish, gobies, clownfish, and most reef inhabitants without issue.

Health & quarantine

This is a hardy, adaptable species with few chronic health problems, though its main risk is starvation in tanks without enough natural algae growth — a visibly pinched belly is the key warning sign to watch for. Quarantine for two to four weeks is good general practice, and like most blennies it lacks scales so should not be treated with copper-based medications. It's also a capable jumper, so a secure lid is worthwhile.