Haplochromis degeni is a species of cichlid endemic to Lake Victoria. It is sometimes placed in the monotypic genus Platytaeniodus, but FishBase leaves it in Haplochromis pending a thorough review of that group. This species grows to a length of 15.4 centimetres (6.1 in) SL. The specific name honours the Swiss ornithologist Edward Degen (1852-1922) who also collected fishes, including the type of this species.