Yellowhead butterflyfish

Background

The yellowhead butterflyfish was first formally described in 1833 by English naturalist Edward Turner Bennett, with the type locality given as Ceylon. It belongs to the large subgenus Rabdophorus, which might warrant recognition as a distinct genus. It has been recorded hybridising with the saddle butterflyfish (C. ephippium).

Its body is pearly white with a golden-yellow band on the head, along the dorsal and ventral parts, and on the fins. The white is broken by greyish blue chevrons. A short black vertical bar runs through the eyes, and a thin yellow line appears on the rear of the operculum. The orange dorsal and anal fins have light black marks on their lower rear parts and yellow margins; the caudal fin is light grey edged in yellow.

Found at depths between 1 and 30 m, it is usually solitary but may form loose shoals of 5-6 individuals around isolated coral heads. It is territorial and aggressive to other chaetodonts, and omnivorous.

Pairs form for breeding; females swell when ready to spawn, scattering eggs into the water for external fertilisation. The spherical eggs float and hatch after 28-30 hours. Larvae develop a bony plate over the head (tholichthys stage) and are pelagic for a long period before maturing into juveniles.