Taxonomy & naming
Nothobranchius bojiensis was described in 1992 by Rosemary Wildekamp and Rudolf Haas, two researchers closely associated with the systematics of East African Nothobranchius during the major taxonomic expansion of the genus through the 1980s and 1990s. The specific epithet bojiensis is a toponym referring to the Boji Plains, a seasonally inundated grassland area in coastal Kenya associated with the lower Tana River system, the species' type locality. Eschmeyer's Catalog of Fishes lists Nothobranchius bojiensis Wildekamp & Haas, 1992 as a valid species within the family Nothobranchiidae.
Nothobranchius is the largest and most intensively studied genus of annual killifish, with well over a hundred described species distributed across seasonally flooded savanna and grassland habitats from the Horn of Africa south to Mozambique and Zimbabwe. The genus has become an important model system in ageing research owing to the extraordinarily short, compressed lifespans of several of its species.
Morphology
As with other Nothobranchius, N. bojiensis is a small, deep-bodied killifish with a blunt head and an upturned mouth suited to feeding at the surface of the shallow, often turbid seasonal pools it inhabits. Breeding males in this genus typically display vivid, species-specific colour patterns — combinations of red, blue, orange and black patterning across the body and fins — used in both territorial display to rival males and courtship of females, while females are uniformly plain and silvery-brown.
Detailed published morphometrics and a precise account of the species' specific colour pattern were not confidently available from the sources consulted here — data sparse, though the general Nothobranchius body plan and dimorphism pattern described above is well established for the genus.
Habitat
Nothobranchius bojiensis inhabits temporary pools within the seasonally flooded Boji Plains grassland system of coastal Kenya, associated with the lower Tana River drainage. These are classic Nothobranchius habitats: shallow depressions in savanna or grassland that fill during the rains and dry completely during the dry season, supporting a fish community adapted to complete its entire life cycle within a single wet-season window.
Because the species depends entirely on the seasonal flooding-and-drying cycle of this specific grassland system, any hydrological change — whether from irrigation diversion, drainage for agriculture, or altered rainfall patterns — poses a direct threat to its continued survival at the site.
Feeding
Nothobranchius as a genus are carnivorous, taking small aquatic invertebrates including mosquito larvae, other insect larvae, small crustaceans and zooplankton from the water column and surface of their temporary pool habitat. This diet is inferred here for N. bojiensis in the absence of a species-specific dietary study, consistent with the genus's generally opportunistic, fast-growing feeding strategy suited to a compressed single-season lifespan.
Mating
Nothobranchius mating follows a well-documented genus-wide pattern that is presumed, though not separately confirmed, for N. bojiensis: males establish loose territories or simply court actively-moving females with intense colour display, and pairs dive together into soft substrate at the pool bottom to deposit and fertilise eggs directly into the mud or leaf litter, repeating the process many times over the course of the breeding season as the pool persists.
Breeding
As an annual species, Nothobranchius bojiensis is expected to follow the diapausing-egg reproductive strategy universal to the genus: eggs are buried in the substrate, the pool dries and the adults die, and the eggs survive for months in the dried mud before hatching en masse when the rains refill the pool. In the aquarium, annual killifish of this genus are typically bred by collecting eggs into a container of moist peat or coconut fibre, storing them dry for several weeks to a few months, and rewetting with soft water to trigger a synchronised hatch. Species-specific incubation timing and clutch size for N. bojiensis specifically were not confidently available from the sources consulted here — data sparse.
In the aquarium
Nothobranchius bojiensis is a specialist killifish-hobby species rather than a mainstream aquarium fish, kept almost exclusively by dedicated annual-killifish enthusiasts prepared to manage the peat-incubation breeding cycle the genus requires. General Nothobranchius husbandry — a small, heavily planted or peat-substrate tank, warm tropical temperatures, and live or frozen foods to support rapid growth — likely applies, but detailed species-specific care notes for N. bojiensis were not confirmed here.
Conservation
Nothobranchius bojiensis is listed by the CARES Preservation Program at the Vulnerable (CVU) priority level. East African seasonal-pool habitats of the kind this species depends on are widely subject to conversion for agriculture and to alteration of natural flood regimes through irrigation and drainage schemes, both of which can eliminate the temporary pools annual killifish require entirely. Because Nothobranchius species are frequently restricted to a single wetland system or a small cluster of nearby pools, localised habitat loss can have an outsized impact on any individual species' persistence, even where the genus as a whole remains diverse and widespread across East Africa.