Studying cichlids enhanced our understanding of speciation and radiation. In contrast, little is known about the evolution of their parasites. Nevertheless, more than half of the species on Earth are parasites. They have to adapt to a living habitat (their host), which render parasites excellent model organisms for speciation research. Lake Tanganyika s (cichlid) biodiversity and its importance as cradle and reservoir of ancient lineages seeding other radiations has resulted in a significant body of literature. Remarkably, until recently virtually no research was carried out into the Tanganyika parasite fauna. With our team, we investigated the monogenean ectoparasites from a wide range of Tanganyika cichlids. This resulted in new species descriptions and the construction of molecular phylogenies. By comparing host and parasite phylogenies we found evidence for co-speciation, within-host (sympatric) speciation and host switching. Aside from host divergence, host ecology appears to play an important role in parasite evolution. Investigating different Tanganyika host lineages demonstrated that Cichlidogyrus saw different speciation pathways in different cichlid tribes, e.g. with variable levels of host-specificity, underscoring the uniqueness of Lake Tanganyika s cichlid flock from a parasitological point-of-view as well.