The fish communities of St Vincent Bay (New Caledonia) and their relation to the benthos were studied by visual censuses. In all, 89 species of fish (31 families) were recorded, the major species in density and biomass being Leiognathus rivulatus, Secutor ruconius, Lethrinus genivittatus and Scolopsis temporalis.  The trophic structure was dominated by macro-invertebrate feeders and plankton feeders whereas piscivores, micro-invertebrate feeders and herbivores were less important. These characteristics are common throughout most of the tropical Indo-Pacific coastal fish assemblages. Species richness of fishes was correlated with the species richness and the abundance of cnidarians whereas fish density and biomass were correlated with the species richness and the abundance of sponges and ascidians. The species structure of the ichthyofauna was also linked to two bottom characteristics, namely siltation and benthos diversity and abundance. Five fish species groups were identified: (1) species of the silted stations where benthic communities were scarce; (2) species usually seen on bare sand bottoms; (3) species occurring where benthic communities were diversified and abundant; (4) species of the “lagoonal grey bottoms”; (5) species occurring where crevices or debris were present with algae. These results support the view that some tropical Indo-Pacific trawl fisheries have declined by modifying bottom habitat rather than by excessive fishing effort.