Blue notho  (Nothobranchius patrizii)

The blue notho is classified as Least Concern (LC) on the IUCN Red List (1).

Although this fish is small and hard to come by, the blue notho (Nothobranchius patrizii) is very popular among aquarists due to its interesting colouration (3). It belongs to a group of small egg-laying fish known as the ‘killifishes’ (4).

As its name suggests, the blue notho is bright blue, and each scale has a darker blue edge (5).

The male blue notho can be distinguished by its vibrant red tail. The female blue notho is not as brightly coloured as the male and is hard to distinguish from females of other Nothobranchius species (5).

The blue notho occurs in Ethiopia, Somalia and Kenya. It is found in seasonal pools in the Lower Tana River basin in Kenya, and in the Wabishebelle River basin in Somalia and Ethiopia (1).

The blue notho occurs in temporary pools, swamps and ditches in coastal plains (2). These temporary waters are created by the seasonal rainfalls and can sometimes be just centimetres deep and dry up extremely quickly (6). However, during heavy wet seasons these pools may be temporarily connected to rivers and streams (3).

The blue notho has a remarkable life history as it lives and breeds in small temporary ponds, which are only present during the wet season (3). Consequently, the blue notho must complete its lifecycle within this brief period (4).

Like other killifish, it is likely that the male blue notho is very territorial, and defends an area against intrusion from all other males (4). As the blue notho must reproduce before its temporary water habitat dries out (3), it is likely to mate with any females that enter its territory (4).

The blue notho lays its eggs in the muddy substrate (6). Due to the blue notho living in often difficult and dry conditions, the eggs it produces are desiccation-resistant, meaning they can endure extreme periods of drought. This adaptation allows the eggs to survive the dry season, when the temporary pools of water dry out (3). The eggs can last for a few years without drying out and as soon as the next rainfall comes, the eggs will hatch (6).

Like closely related species, the blue notho usually feeds on insects, aquatic insect larvae, and crustaceans (4).

The blue notho is not currently known to be facing any major threats (1).

There are currently no specific conservation efforts known to be in place for the blue notho (1).

Find out about killifish conservation: 

• International Killifish Conservation Programme:
  http://www.killi.org/ikcp/