ABSTRACT: Spatial and temporal variations in abundance of ectoparasites from 7 coral reef fish species [Hemigyrnnus melapterus (Labridae), Siganus doliatus (Siganidae), Scolopsis bilinea tus (Nemipteridae), Thalassoma lunare (Labridae), Scarus sordidus (Scaridae), Ctenochaetus striatus (Acanthuridae), and Acanthochromis polyacanthus (Pomacentridae)] at 2 locations, Lizard Island and Heron Island in the Great Barner Reef, were investigated. The study demonstrates that there is a significant species-specific parasite fauna which is conserved over space and time. Host identity explained most of the variation in parasite composition and abundance while host size explained a smaller proportion of the variation. For each species the parasite assemblage showed little variation among local, but physically varied, sites. Species-specific patterns of parasite abundance were similar between widely separated locations, although there were more categories of parasites at the northern location Lizard Island. Parasite numbers and species composition among fish species at Lizard Island did not vary among collection times except for S. doliatus, which had a 7-fold increase between May 1992 and January 1993, mainly due to dactylogyridean monogeneans. Parasite abundance was positively correlated with fish standard length for 3 fish species.