Korthaus’ killifish  (Nothobranchius korthausae)

Classified as Vulnerable (VU) on the IUCN Red List (1).

Korthaus’ killifish is a small, striking fish of which there are two colour varieties: a yellow variety and a red variety (3). Individuals of the yellow variety are a metallic yellowy-brown with brown-black stripes on the larger fins and have golden coloured eyes (4). The red variety, discovered more recently, is a deep red with fainter stripes. In both varieties the male tends to be the brightest of the sexes and possesses larger fins (3). 

Korthaus’ killifish is endemic to Mafia Island in eastern Tanzania (2), although it exists all over the world in domestic aquaria (4).

Korthaus’ killifish inhabits pools and ditches near marshland. Although the island of Mafia does not have a river it does have enough rainfall and groundwater to maintain the pools all year round. Due to the groundwater origin of these pools, they are often rather salty (3).

Like other members of the genus Nothobranchius, Korthaus’ killifish is referred to as an ‘annual killifish’, indicating that it has a short life span of usually one year or less. This is due to the fact that the water bodies this species lives in typically do not last very long, so it completes its life cycle quickly, before the habitat disappears (4).

Korthaus’ killifish lays its eggs at the bottom of a temporary pool before the dry season commences. With the arrival of the dry season and the desiccation of the pool, the adult killifish dies, leaving the eggs to continue the survival of the population. Embedded in the muddy soil (5), the eggs are able to withstand these dry conditions for one to three months (2) (5), until the rains fall once again, the eggs hatch and the larvae grow quickly to sexual maturity (5). 

This fish is threatened in the wild due to its limited distribution, which makes it highly susceptible to any habitat destruction or degradation (1).

There are currently no specific conservation efforts known to be in place for this species (1). However, Korthaus’ killifish is popular in aquariums due to its attractive colouration (3), which could act to safeguard its future, should a catastrophe befall its natural habitat. 

View information on this species at the UNEP World Conservation Monitoring Centre.