Original description as Haplochromis marginatus:
- Trewavas, Ethelwynn. 1935. "A Synopsis of the Cichlid Fishes of Lake Nyasa". Annals and Magazine of Natural History. Series 10; pp. 65-118 (crc00118)
Conservation: Protomelas marginatus is evaluated by the international union for the conservation of nature in the iucn red list of threatened species as (LC) least concern (2018). Protomelas marginatus appears common in certain areas and lives often deeper than the reach of beach seines.