How organisms adapt to different environments and form new species is a central question in evolutionary biology. Cichlid fish of the East-African Great Lakes are the most diverse species assemblage of vertebrates on our planet. Even though they have become a model for speciation research, how and why they reached this enormous diversity remains difficult to explain based on current insights. One theory is that cichlids evolved through habitat diversification (e.g. adaptation to a substrate type), trophic diversification (evolution of different feeding strategies and adaptation to a specific diet) and communication diversification (e.g. evolution of different social interactions including colour- and odour-based mate recognition). However, different habitats, diets and social interactions might also lead to exposure to different parasite communities. This latter aspect will be surveyed in this project.