Blue-cheeked butterflyfish

The blue-cheeked butterflyfish, Chaetodon semilarvatus, is a species of butterflyfish (family Chaetodontidae). It is found in the Red Sea and the Gulf of Aden, at depths of between 3 and 20 m.
This species is one of the few fish species to have longterm mates.
Its length is up to 23 cm (9.1 in). It is mostly yellow, with thin slate blue vertical lines on the sides and a slate blue cheek patch in lieu of the usual black eyestripe of most Chaetodon.