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 SL.
The specific name honours the Swiss naturalist Edward Degen (1852-1922) who collected fishes, including the type of this species.