Common name for a species of marine reef-fish, with the scientific name
Pomacanthus semicirculatus. Juveniles (fig.) look very different in pattern and colouring from adults. Immature fish are dark yellowish to brown-grey, with a faint pattern of small blackish spots encircled with a lighter shade of grey. This pattern is overlaid with another pattern of thin white and vivid blue lines, of which the latter towards the end often break up into tiny spots. At the front the stripes are fairly straight but they become increasingly curved toward the rear of the body, where they form semicircles, a feature that gave rise to this species' Latin name, as well as to another common name also used, i.e. Semicircle Angelfish (fig.). The pectorial fins are transparent and yellow in colour, whilst the area around the snout is also yellowish. As it matures, the greyish-brown body
colour at the centre changes little by little into yellowish, while the pattern of thin lines slowly fades away (fig.), until the transition is complete and the adult pattern is achieved fully. Adults have a mostly pale brownish-yellow body, with fins and a tail that are rimmed in bluish-green and with scales that have a blue base, which give the fish a speckled appearance. Koran Angelfish are deep-bodied, laterally compressed, and can grow to a length of around 35 centimeters.