Jewelled Blenny

Overview

The Jewelled Blenny, also sold in the aquarium trade as the Lawnmower Blenny, is a small, well-camouflaged combtooth blenny of Indo-Pacific reefs. It perches on rocks and coral and can shift its colour to match its surroundings. It is often seen alone.

Distribution & habitat

It ranges from the Red Sea and East Africa east to Samoa. It reaches north to the Ryukyu Islands and south to the Great Barrier Reef and New Caledonia. Look for it on reef flats, shallow lagoons and seaward reefs. It also lives in estuarine areas, especially where algae-covered rubble, mixed coral and sand, or weedy rocks and coral outcrops occur.

Appearance

The body is elongated and olive to brown. It has dusky bars, many pale spots of varying size, and dark streaks toward the front. Dark lines usually run along the front of the body. Small blue spots with dark outlines often mark the rear. The dorsal fin has no notch. Adult males have extended front rays on the anal fin.

Biology & behavior

This blenny is a facultative air-breather. It can change the intensity of its colours to hide from predators.

Feeding

It scrapes food from hard surfaces. Despite the "lawnmower" name, it is mainly a detritivore, and plant material makes up only about 15% of its diet. It also takes in tiny invertebrates and diatoms.

Reproduction

It is oviparous. Females lay sticky eggs on the bottom, each attached to the surface by an adhesive pad. The larvae drift in the plankton in shallow coastal waters.