About Chaetodon speculum Cuvier, 1831
The mirror butterflyfish, also called the oval-spot butterflyfish, has the scientific name Chaetodon speculum Cuvier, 1831, and is a species of butterflyfish in the family Chaetodontidae. This species is distributed across the Indo-Pacific, ranging from Indonesia to Japan, and south to the Great Barrier Reef and Papua New Guinea; it has also been recorded from Madagascar, Mauritius, and Réunion. It reaches a maximum length of 18 cm (7 in). Its dorsal fin has 14 spines and 17 to 18 soft rays, while its anal fin has 3 spines and 15 to 16 soft rays. Its body ranges from bright to orange-yellow, with a large black blotch below the dorsal fin and a vertical black bar that runs through the eye. Chaetodon speculum was first formally described in 1831 by French anatomist Georges Cuvier (1769–1832), with its type locality given as Jakarta. Along with other butterflyfish that have angular yellow bodies, black eyestripes, and a single differently colored patch—an exception being the relatively basal blue-lashed butterflyfish, C. bennetti—it is classified in the subgenus Tetrachaetodon. Within this group, it appears to be particularly closely related to the Zanzibar butterflyfish (Chaetodon zanzibarensis), which has a smaller black blotch and faint horizontal stripes on its flanks. If the genus Chaetodon is split into separate genera, the subgenus Tetrachaetodon would be placed in the genus Megaprotodon. The mirror butterflyfish inhabits coral reefs at depths of 3 to 30 meters. It prefers coastal reef slopes that have abundant hydroids and sea anemones. Small juvenile individuals hide within coral thickets. This species is typically solitary, and it is relatively uncommon. It feeds on coral polyps and invertebrates.
