It lives in a tube it did not build. Blennies of this group take over the abandoned limestone tubes of tube worms, and similar narrow holes in the reef, back into them tail first, and spend the day with only the head showing at the opening. Approach and the fish is gone; back off and wait half a minute and the head is at the same hole again.
Going in backwards takes a particular body: long, round in section, flexible along its whole length. That is why this fish looks nothing like the stubby blennies that perch on top of coral heads. It swims differently too, undulating the whole body like a small eel instead of rowing with its pectoral fins.
Despite the pair of large curved canines in the lower jaw that the genus is named for - Aspidontus, shield tooth - it is mostly a grazer, taking algae, detritus and small invertebrates off rock.
It is a near twin of the false cleanerfish, its own congener, but longer and plainer. That one runs a confidence trick on other fish for a living. This one does not.
The genus. Aspidontus Cuvier 1834 - aspis (viper) + odon (tooth). ETYFish
The species. Aspidontus dussumieri (Valenciennes 1836) - Honours Jean-Jacques Dussumier. ETYFish
- long slender body, blue-gray with a dark stripe from snout to tail
- backs into an empty worm tube and watches from the entrance
- elongated jaws with a pair of large curved canines in the lower jaw
- swims with a whole-body undulation rather than with the pectoral fins
- up to 12 cm
Why it's threatened
There are no known major threats.
Threat classification from the IUCN Red List.
