Nothobranchius

Type locality is 'Rufiji River near Utete, eastern Tanzania', and this species is apparently endemic to the lower Rufiji including the Selous Game Reserve and freshwater parts of the Rufiji delta region. Populations in the aquarium hobby include 'Rufiji river camp', 'Kikongono', 'Ruhoi River', 'Kanga', 'Utete', 'Saadani Game Reserve', 'Ruvu River', 'Bagamoyo', 'Makurunge', 'Killimani', 'Chamakwese', 'Nyamwage', 'Mohoro', and 'Ukuni'.

Inhabits ephemeral, water-filled depressions, pools and swamps mostly located in lowland floodplains. Water levels in these seasonally-variable habitats typically decrease during the dry season and eventually become completely dessicated for several months each year. Near Bagamoyo it's been collected from pools of a flat, grassy floodplain alongside the congeners N. annectens, N. janpapi and N. melanospilus, while at Soga it occus together with N. janpapi and N. ocellatus. Most habitats appear to be heavily overgrown with terrestrial vegetation.

Described from close to the city of Beira, Mozambique and for many years thought widely-distributed between the Kruger National Park, South Africa to the Kwa-Kwa River north of the Zambezi delta. Populations from the south and north of this range exhibiting differences in colour pattern and morphology have now been described as N. pienaari and N. krysanovi, respectively, meaning N. rachovii sensu stricto is restricted to the area between the lower Pungwe and Zambezi river basins in eastern Mozambique.