The Neotropical freshwater fish fauna represents 20% of the known fish species diversity. Although several historical and ecological mechanisms involved in the distribution of this diverse ichtyofauna have been explored, few studies have analyzed a complete community. Here, we report a study of the distribution and diffusion of eco-morphological traits across the phylogeny of the fish community of the Maroni Basin, located at the border between French Guiana and Suriname. We also test the eco-morphological hypothesis stating that morphology can be used as a predictor of ecology. Nuclear (five markers) and mitochondrial (one marker) sequences of 236 species were collected to reconstruct their phylogeny, morphometric measurements of 680 individuals were taken and a data table of each species' general ecology was compiled. Multivariate analyses showed a strong structuration of morphometric data on the axes segregating the orders and successive ranks. Axis 1 (27.14%) was a component of shape, and separated compressed, deep-bodied big-eyed fishes (negative values) from depressed, long-snouted fishes with small eyes positioned upward (positive values). The second axis (25.47%) was mainly related to fin-based locomotion and showed a negative correlation between length of anal fin (negative values) and the relative area of pectoral, dorsal and caudal fins. Ecological traits showed a more diffuse pattern since some niches can be occupied by several species belonging to different orders. Co-inertia analyses showed that morphological and ecological traits were significantly linked (RV=0.23; p<0.001) but that this correlation becomes very weak once the influence of phylogeny is removed (RV=0.05; p<0.02), thus challenging the universal application of the eco-morphological hypothesis. Furthermore, Abouheif tests showed that all ecological and morphological traits, as well as the main co-variations between them, were significantly auto-correlated to phylogeny. Evolutionary patterns of some of these traits were mapped across the community's evolutionary tree: thus we observed that shifts to a benthic lifestyle occurred twice during the evolution of Characiformes and Siluriformes and that they were both times simultaneously followed by body depression and anal fin reduction, and that body depth and relative eye size have a tendency to co-evolve.