Butterflyfishes have evolved critical relationships with scleractinian corals and are extremely vulnerable to widespread reef degradation and coral loss. Temporal changes in composition and abundance of butterflyfishes has been documented at Lizard Island, northern Great Barrier Reef, which has been subject to several recent and major disturbances. The purpose of this study was to examine temporal changes in the social structure (sociality) of the Chaetodon butterflyfish assemblage at Lizard Island to explore implications for reproductive viability of remaining individuals after disturbance. We predicted that declines in the abundance of butterflyfishes caused by depletion of prey resources, would disrupt social systems leading to declines in proportion of indivduals found in pairs. Sampling was undertaken to quantify the abundance and sociality of butterflyfishes at Lizard Island, testing for changes in the proportion of individuals that occurred in pairs in 2002, 2009 and 2017. While there is an unequivocal decline in the abundance and diversity of Chaetodon butterflyfishes after coral loss, the effect upon sociality was variable across species. Overall coral loss led to a significant negative effect on sociality, but this varied greatly amongst species, from a significant negative effect (C. baronessa) to no significant effect (C. citrinellus and C. vagabundas).