Red Victoria nothobranch
Nothobranchius robustus is a species of killifish in the family Nothobranchiidae. It is found in the Lake Victoria basin, the Lake Albert basin, the Sio River and near Ahero in Kenya, Tanzania, and Uganda.
Its natural habitats are rivers, intermittent rivers, swamps, and intermittent freshwater marshes. This species was described in 1935 by Ernst Ahl from types collected in northwestern Tanzania.
In Nature Nothobranchius robustus is found in marginal, ephemeral, zones of permanent water bodies such as flowing creeks in papyrus swamps, small streams and dead river branches. Usually inhabits the more shallow and quiet parts between bordering vegetation, occasionally in temporary pools.
Their increasing popularity of Nothobranchius stems from the extremely short lifespan that is the result of their specific life‐history adaptations. In the aquarium, adults of different Nothobranchius species and populations live between 3 and 18 months and, notably, there is a negative correlation between the captive lifespan of a species and the aridity of their habitat. Their short lifespan is coupled to rapid age‐dependent functional decline and expression of cellular and molecular changes comparable to those observed in other vertebrates, including humans.
Nothobranchius robustus males are characterized by pale blue scales with narrow red margins at the anterior part of the trunk, usually resulting in the blue body colour becoming increasingly red towards the posterior part of the body where wide scale margins result in an almost completely red colouration. The unpaired fins and the ventral fins are completely red. The caudal fin usually has a narrow black margin. The intensity of the general red colouration may vary across populations.
Females are yellow-brown, with transparent fins.
Nothobranchius sp. primarily feed on macroinvertebrates. Their diet appears opportunistic and largely depends on prey availability. It contains both pelagic and benthic preys. They prefere to feed on small crustaceans (Cladocera, Copepoda, Ostracoda and Conchostraca) and on aquatic insect larvae.
This species has a semi-annual life cycle.
All Nothobranchius species have a polygynandrous mating system, in which both males and females have multiple mating partners during a breeding season.
Both males and females continue growing rapidly after sexual maturity and only attain the inflection point in they have growth curves later in adulthood. The increase in age and body size is associated with an increase in fecundity, from an initial production of 2-10 eggs to hundreds of eggs each day when resources are abundant.
This species has a semi-annual life cycle. Nothobranchius egg is deposited in the pool substrate, where it remains until the pool desiccates.
Embryonic development under captive conditions in peat moss is about three to four months at room temperature.
