The diversity and biogeography of three dominant cichlid genera (Australoheros, Gymnogeophagus and Crenicichla) is reviewed within the Argentinean province of Misiones based on newly collected material specifically for this study. The results have revealed strikingly different structuring and origin of diversity between the three genera with implications for a future PhD study. The biogeographic implications of the reconstructed phylogenies using mitochondrial DNA have been compared with the geological history of the area revealing many new insights.