A blenny that eats coral, and there are very few of those. It rasps the living tissue off branching corals with a mouth full of fine comb teeth, working Acropora, Pocillopora, Seriatopora, Porites and fire coral, and leaving pale grazed scars along the branches.
The male turns that damage into a nest. He picks a coral head and overgrazes one patch of it down to bare white skeleton, and the female lays on the cleared surface, where the eggs hold by an adhesive pad until they hatch. It makes the nest visible from several meters away: find a small bald patch on an otherwise healthy coral, and the fish is usually sitting within arm's reach of it.
The sexes are marked apart unusually clearly for a blenny. Both are cream and covered in dense round spots, but the male's spots are red and the female's are dark brown.
It is a shallow fish, mostly between 3 and 8 m on reef tops, and it depends completely on live coral. That is the problem with it: live branching coral is the first thing a hot summer takes away.
The genus. Exallias Jordan & Evermann 1905 - exallos (quite different). ETYFish
The species. Exallias brevis (Kner 1868) - short. ETYFish
- cream body under dense round spots - red in males, dark brown in females
- high blunt head with a fringe of cirri across the nape
- sits on branching coral, often beside a bare grazed patch
- up to 14.5 cm
Why it's threatened
Threat classification from the IUCN Red List.
