Glassy sweeper

Photo: Mark Hulme · CC BY-NC

Glassy sweepers form dense copper-coloured shoals of thousands of fish in the cave-like overhangs and crevices between the Bookends pinnacles. Their large eyes and compressed body shape are adaptations to life in dim, sheltered habitats. At dusk they migrate out onto the reef to feed on zooplankton, and a timed night dive during this mass emergence is one of the most dramatic spectacles the site offers.