About Chaetodon mertensii Cuvier, 1831
Chaetodon mertensii reaches a maximum total length of 12.5 cm (5 inches). Its body is white, with 5 to 7 chevron-shaped dark grey bands along its sides. The rear portion of its trunk, the adjacent dorsal and anal fins, and the rear portion of the caudal fin are orange or yellow. An unbroken vertical black bar crosses the eye and extends over the nape; this differs from similar species, which have a separate nape spot and separate eyestripe. This species occurs in deep lagoons and seaward reefs, at depths between 10 and 120 meters. It feeds on algae and small benthic invertebrates. Its native distribution is in the Pacific Ocean, ranging from the Ryukyu Islands to the Philippines, and extending south and east to Lord Howe Island, Rapa Iti and the Tuamotus. It was first recorded in the Kermadec Islands Marine Reserve north of New Zealand in 2015, after researchers reviewed hundreds of hours of unused documentary film footage.
