Bluefin Notho, Rachow's Notho, Rainbow Notho (Nothobranchius rachovii) care guide

Group
Freshwater fish
Other names
Bluefin nothobranch, Bluefin notho
Family
Nothobranchiidae (African killifishes)
Origin
Mozambique: seasonal pools and swamps on the floodplains of the lower Pungwe and lower Zambezi rivers, around Beira. The pools dry out completely every year.
Water
freshwater
Maximum size
5.5 cm
Temperature
20–24°C
pH
6–7.5
Hardness
Soft to medium, 3–10 dGH
Minimum tank
41 litres
Care level
intermediate
Temperament
semi_aggressive
Lifespan
6–12 months years

Care

One of the most colourful killifish of all, and an annual species: in the wild the adults live only as long as their pool holds water. Expect roughly 6–12 months in the aquarium (Wikipedia mentions up to a year and a half), so it is a fish for people happy to keep it going from eggs year after year. Keep a pair, or one male with two or three females so no single female gets all the attention, in a species tank. A tank with a base of about 45 × 30 cm (around 41 litres) is enough for a pair. Use gentle filtration – an air-driven sponge filter suits it – and a soft, dark substrate or a layer of peat, with a few plants or a clump of fine-leaved cover where females can rest. Fit a tight lid: like most killies, these will jump. Keep the water fairly cool to warm at 20–24 °C, soft to medium and slightly acidic to neutral (pH about 6–7.5). Wild pools are acidic to neutral. Regular partial water changes keep the fish in good shape, but avoid big swings in temperature or chemistry. Males are larger and far brighter than females, with alternating light blue and orange-red bars over the body and fins. Females are plain brownish, with a reflective pale-blue spot on the flank scales. Wikipedia describes several colour forms, including the typical orange-and-blue fish, a darker 'KNP Black' and a 'Red' with a red head and turquoise highlights. N. krysanovi and N. pienaari were once treated as populations of N. rachovii and are now separate species, so older fish labelled 'rachovii' may belong to either. In the hobby this fish is sold under population or collection codes such as 'Beira 98' or 'MOZ 99/1', and the original 1958 import is still kept as a separate strain. Keep each population separate and pass the code on with eggs or fish, so lines don't get mixed. Almost everything sold is hobby-bred. FishBase lists it as Least Concern on the IUCN Red List, but also notes it can be hard to maintain. Sources: Seriously Fish (seriouslyfish.com/species/nothobranchius-rachovii/); FishBase (fishbase.se/summary/Nothobranchius-rachovii.html); Wikipedia (en.wikipedia.org/wiki/Nothobranchiusrachovii). Checked October 2026.

Diet

A micropredator that needs small live or frozen foods such as Daphnia, brine shrimp (Artemia) and bloodworm. Feed small amounts often; these fish grow and mature very quickly and need plenty of good food to do so. Dry foods are not a substitute for live and frozen fare.

Breeding

An annual killifish whose eggs survive drying out. Give the fish a dish or layer of peat to spawn into; they dive into it and lay eggs one at a time over several days. Remove the peat, squeeze it until only damp (not wet), and store it in a closed bag or tub at around 21–25 °C. Seriously Fish gives an egg storage time of 5–7 months; check a few eggs for developed eyes before wetting. To hatch, cover the peat with shallow, soft water. Fry need infusoria or the very smallest foods first, then brine shrimp nauplii, and grow very quickly; sources differ on how soon they mature, from a few weeks (Seriously Fish) to about 12 weeks (FishBase, Wikipedia).

Compatibility and tank mates

Not a community fish. Keep it in a species tank, as a pair or one male with two or three females. Males are rough with each other and with females, so do not crowd several males together unless the tank is large and well broken up. Avoid mixing with other Nothobranchius species: females of different species look very alike and are easily confused.

Last updated 4 October 2026. Community-edited care guide on Aquatic-Auctions.

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