Dark capped parrotfish

The dark-capped parrotfish is a small grazer of Indo-Pacific reefs, reaching about 35 cm. It has picked up a whole string of common names, from blue parrotfish to egghead and yellow-barred parrotfish, which tells you how differently the sexes look. Males wear a dark hood over the front of the body. Females go the other way and carry yellow bars. You meet it in lagoons and on coastal and outer reefs in the top 20 m.

Also known as: dark capped parrotfish, egghead parrotfish, yellow-barred parrotfish, darkcap parrotfish, egghead parrotfish, darkcapped parrotfish, yellow-barred parrotfish, dark-capped parrotfish, dark capped parrotfish, dark-capped parrotfish, darkcap parrotfish, darkcapped parrotfish

The fish to rule out is the yellowbarred parrotfish, Scarus dimidiatus, which looks much the same at a glance. Check the shoulder, in the gap between the eye and the base of the pectoral fin. Scarus dimidiatus has a bar there with a pale centre. This species has none, so a clean, unbroken shoulder settles it. Early-phase fish also carry fewer slanting bars on the back, and those bars lie flatter rather than standing upright.

Males are marked by a dark area that spreads over the head and onto the body, so the front of the fish looks shaded compared with the rest. Females and other early-phase fish are barred with yellow, and carry a small number of dark, slanting bars across the back. Terminal males are less brightly blue on the upper head and back than some of their close relatives.

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  Bicolour parrotfish

  Cetoscarus bicolor

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  Bleeker's parrotfish

  Chlorurus bleekeri

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  Blue-barred parrotfish

  Scarus ghobban

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  Bridled parrotfish

  Scarus frenatus

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  Carolines parrotfish

  Calotomus carolinus

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  Chameleon Parrotfish

  Scarus chameleon