- EnglishName: Masked bannerfish
- Local Name : Maasku bibee
- Size : Max. 25 cm
- Family: CHAETODONTIDAE
- Order : Perciformes
- Distinctive Characters: Dorsal fin with 12 spines and 24-27 rays. Anal fin with 3 spines and 17-19 rays. Pectoral fin with 16-18 rays. Body depth 1.5-1.7 in standard length. The fourth dorsal spine prolonged as a tapering white filament. Adults with a prominent hump on nape and a short “horn�? in front of each eye.
- Colour: Three dark brown bars. Central bar narrows at the top to include only fifth to seventh dorsal fin spines. Areas between bars white. Posterior part yellow.
- Habitat and Biology: Adults usually found in pairs that shelter in coral crevices, in outer reef slopes. Feed on bottom living animals.
- Distribution: Indo-Pacific.
- Remarks: Heniochus monoceros is a fairly common species in the Maldives. It is seen hovering side by side
below table corals. However, this is one of the most timid of all bannerfish.