CHAETODONTIDAE Hemitaurichthys zoster, 11.5 cm SL (photo by Ukkrit Satapoomin) Hemitaurichthys zoster (Bennett, 1831) Black Pyramid Butterflyfish D XI-XII, 24-26; A III, 20-21; P1 17-19; LLp 67-73. Body oval; snout short, pointed; predorsal contour nearly straight, with a slight hump at nape. Lateral line complete. Pectoral and pelvic fins elongate; caudal fin slightly round. Color: dark brown with a very wide white bar in middle-anterior part of body, broader ventrally; outer part of dorsal spines above white bar yellow; caudal fin white with a brown posterior border. Size: maximum length about 16 cm. Distribution: Indian Ocean, from East Africa and Red Sea to Andaman Sea. Remarks: inhabits coral reefs and aggregates in midwater at depths of 5-40 m. Forms small to large aggregations. Feeds on plankton.