Blue-spotted Bristletooth

Ctenochaetus marginatus has its dorsal fin supported by 8 spines and between 26 and 29 soft rays while its anal fin is supported by 3 spines and 24 to 26 soft rays. The shape of the body is a highly laterally compressed, elongated oval with a steep dorsal profile on the head. The eye is positioned high on the head. The small, protrusible mouth has thick lips and there are many flexible teeth with curved tips in each jaw. The overall colour is dark greyish-brown marked with a dense pattern of small blue spots over the head and body. The dorsal, anal, pelvic and caudal fins have blue stripes on them. This species has a maximum published total length of 27 cm (11 in).

Ctenochaetus marginatus has a discontinuous rather localised distribution across the tropical central and eastern Pacific. In the central Pacific it is found in the Marshall, Caroline, Kiribati, Tuvalu, Johnston, Marquesas, Society and Line Islands. While in the tropical eastern Pacific its range runs from Costa Rica south to Colombia, including Clipperton Atoll, Cocos and Gorgona. This is a benthopelagic species found at depths between 2 and 18 m (6 ft 7 in and 59 ft 1 in) on shallow seaward reefs with small schools sometimes occurring in turbulent water in the surge zone where it feeds on algal film.

== References ==

Ctenochaetus marginatus has the specific name marginatus, meaning "bordered" or "edged", which is a reference to the band on the bases of the dorsal and anal fins.