Translucent gold fish packing a cave so densely that the rock behind them disappears.
To about 10 cm, translucent gold to amber with a silver belly, large eyes and a slender tapering body. The internal organs and the spine are visible through the flanks, and a dense school in a lit cave has a distinctive glassy quality. Larger, more heavily built sweepers of the genus Pempheris often share the same overhang and are opaque brown-copper.
Schools of hundreds to thousands fill caves, overhangs and wreck interiors through the day, moving as a single mass around the space, and leave at dusk to take zooplankton in open water. Bioluminescent bacteria housed near the gut give the fish a faint glow that is not visible to a diver but is thought to serve in counter-illumination. Photographing them means working with a mass that reforms around the intrusion; a wide lens from inside the school gives more than a frame from outside it. Recorded from about 3 to 35 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.