The fish that fills the blue water above a reef, and the main prey of everything that hunts there.
To about 35 cm, blue-grey over the head and back, pale below, with a bright yellow rear third and tail. Fusiliers are close relatives of the snappers with a protrusible mouth adapted to picking plankton, and they occupy the water column rather than the reef itself.
Schools of hundreds to thousands move along slopes through the day and are the standing food supply for trevallies, mackerel and groupers; a school suddenly compressing into a ball is usually the first sign of a predator that a diver has not yet seen. At night the fish settle into the reef and take on a red-brown resting colour. They are constantly moving and are easier to photograph as a mass than as individuals. Recorded from about 3 to 45 m.
Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.