Rusty Blenny

Overview

The rusty blenny is a small, scaleless marine fish often found in shallow, sunlit rocky areas. It is a shy, territorial species known for its distinct homing behavior and ability to perform quick, darting movements between rocks.

Distribution & habitat

This species is native to the eastern Atlantic, ranging from the Loire in France to Morocco, and is also widespread throughout the Mediterranean and Black Seas. It typically inhabits very shallow waters, often staying within one meter of the surface, where it frequents rocky crevices and areas covered in filamentous algae.

Appearance

The rusty blenny has a slender, laterally compressed body that is often described as pot-bellied toward the front. Its coloration is variable, featuring grayish tones marked with dark and light vermicular spots or stripes. Key identifying features include a short, fringed appendage above each eye, red spots on the pectoral and tail fins, and a small black spot typically located between the first two rays of the dorsal fin.

Biology & behavior

This diurnal fish is solitary and highly territorial. It is known for its "flight"-like swimming, where it covers significant distances between rocky outcrops. Despite its timid nature, it can often be spotted in tide pools or near shorelines. It is a harmless species that relies on its camouflage to blend into algae-covered substrates.

Feeding

The rusty blenny is primarily herbivorous, feeding almost exclusively on algae, with a particular preference for Ulva species. Some observations suggest a more diverse diet that may occasionally include small invertebrates.

Reproduction

Spawning occurs from May to July. The species is oviparous, with females laying adhesive, demersal eggs in hidden locations such as rock cavities or under stones, where they are guarded.