Teleostei (teleosts) >
Cichliformes (Cichlids, convict blennies) >
Cichlidae (Cichlids) > Pseudocrenilabrinae
Etymology: Placidochromis: Latin, placidus = of peaceful or tranquile appearance + Greek, chromis = a fish, perhaps a perch (Ref. 45335); longus: From the Latin "longus" = long, elongate, referring to its elongate body shape (Ref. 55898).