Bluefin notho
An annual killifish whose entire life happens between one rainy season and the next. Bought by people who do not know that, it looks like a fish that died young; kept by people who do, it is one of the few aquarium animals whose natural history is visible in the tank.
Quick profile
- Scientific name
- Nothobranchius rachovii
- Adult size
- 4–5.5 cm (1.6–2.2 in)
- Lifespan
- 1–2 years
- Temperature
- 22–26 °C (72–79 °F)
- pH
- 6–7.5
- Hardness
- 3–12 °dGH
- Minimum tank
- 40 L (11 US gal)
- Minimum length
- 50 cm
- Swimming zone
- Bottom
- Social
- Harem
- Diet
- Insectivore
- Overall confidence
- low confidence
What keeping this species involves
Short-lived by design, dependent on live food, intolerant of hard alkaline water, and reproduced only through a dry incubation period. None of that is difficult; all of it has to be intended.
Seasonal pools on the coastal floodplain that fill in the rains and dry out completely.
Identity and names
- Common name
- Bluefin notho
- Scientific name
- Nothobranchius rachovii
- Family
- Nothobranchiidae
- Order
- Cyprinodontiformes
- Class
- Actinopterygii
- Also sold as
- Rachow's nothobranch, bluefin nothobranch, Nothobranchius rachovii
Name ambiguity
Fish traded as Nothobranchius rachovii come from several populations, and part of what was once included under the name has been described separately as N. pienaari. Trade stock is identified by collection locality code rather than by name, and a fish sold without one cannot be placed to species with confidence.
Adult size and growth
4–5.5 cm (1.6–2.2 in) — Males larger and deeper-bodied than females.
Typical lifespan in an aquarium: 1–2 years. Almost every animal sold in a shop is a juvenile, so the tank has to suit the size in the first line rather than the size in the bag.
Water and tank requirements
A male with two or three females is a group, and the group-space reasoning behind AquariumHQ's tank-length rule applies to it even though the fish are small and the tank is a species tank. The peat spawning base sets the substrate rather than the footprint.
| Requirement | Value | Notes |
|---|---|---|
| Temperature | 22–26 °C (72–79 °F) | Stability matters more than hitting an exact figure. |
| pH | 6–7.5 | A stable pH outside the ideal band is usually better than an unstable one inside it. |
| General hardness | 3–12 °dGH | Check your supplier's published figure before choosing species. |
| Minimum volume | 40 L (11 US gal) | A floor, not a recommendation. |
| Minimum footprint | 50 cm long | A male with two or three females is a group, and the group-space reasoning behind AquariumHQ's tank-length rule applies to it even though the fish are small and the tank is a species tank. The peat spawning base sets the substrate rather than the footprint. |
| Water flow | still | Match the outflow to this rather than to the filter's rating. |
| Lid required | Yes | This species jumps. |
| Structure | A peat or coir spawning base and dense cover. Bright, bare, strongly filtered tanks suit it badly. |
Behaviour
- Hovers close to the base and spawns by diving into the substrate.
- Males colour up within days of being introduced to a female.
Telling males from females
Males are red and blue with barred fins. Females are plain grey-brown and are frequently mistaken for a different species.
Feeding
Dry food is often refused outright. This is a species that needs live or frozen food planned for rather than attempted.
- Diet type
- Insectivore
- Staples
- Live and frozen bloodworm, Live blackworm and grindal, Frozen brine shrimp
Breeding
- Strategy
- Egg-burying in peat, incubated damp for several months before wetting
- Difficulty
- challenging
- Parental care
- none
The eggs enter developmental arrest and need a dry-incubation period. Wetting them too early produces belly-sliders; too late and viability falls.
Tankmates and compatibility
Assessments are derived from stored traits by the compatibility engine, with the reasoning shown. A verdict is a statement about probability, not a guarantee — individual temperament can override it.
| Towards | Risk | What it means |
|---|---|---|
| Small fish | none | Anything that fits in the mouth is at risk once this species reaches adult size. |
| Adult dwarf shrimp | moderate | Cover reduces losses but rarely prevents them where the risk is high. |
| Shrimplets | high | Determines whether a shrimp colony can grow rather than merely persist. |
| Snails | none | Applies to snails you wanted as well as snails you did not. |
| Long or trailing fins | none | Fin damage is an entry point for secondary infection. |
| Plants | none | Tough species such as Anubias and Java fern survive most grazers. |
Any pair in the catalogue can be assessed with the compatibility checker.
Welfare considerations
Points where the way this species is commonly sold or kept differs from what it actually needs.
- Lives about a year. A death at twelve months is the end of a normal life, not a husbandry failure, and keepers who do not know that treat the tank for a disease that is not there.
- Sold without a collection locality code the identity cannot be confirmed, and populations should not be mixed.
Problems to watch for
Most problems in a tank containing this species are general rather than species-specific. Start with the troubleshooting index and work from the observation rather than from a guess at the cause.
What AquariumHQ does not yet hold
Species-level disease susceptibility is modelled in the graph and is not yet populated. Health pages will not be published until each condition has veterinary sourcing, because health content written without evidence is the most harmful thing this product could publish. The gap is recorded in the coverage report.
Where it comes from
- Native range
- Coastal plain of southern Mozambique
- Habitat
- Seasonal pools on the coastal floodplain that fill in the rains and dry out completely.
What the checklists say
6 distribution statements retrieved from GBIF checklists. Establishment means is reproduced from the source where it states one, and left unstated where it does not — a record of presence is not a record of origin.
| Status | Places | What this means |
|---|---|---|
| Native | 3 | A checklist states the species occurs here naturally. |
| Recorded as present, establishment means not stated | 3 | The source records the species as present and does not say whether it is native or introduced. AquariumHQ does not fill that in. |
Evidence
Every stored value with the kind of support behind it and where to check it. Evidence type and confidence are separate axes: an editorial position held confidently and a measurement held tentatively are different things.
| Claim | Value | Evidence type | Confidence | Source |
|---|---|---|---|---|
| scientific name | Nothobranchius rachovii | Observed / measured | high confidence | Catalogue of Life; GBIF — Global Biodiversity Information Facility |
| native range | Coastal plain of southern Mozambique | Observed / measured | moderate confidence | GBIF — Global Biodiversity Information Facility |
| adult size | 4–5.5 cm | Aquarium-literature consensus | low confidence | AquariumHQ husbandry synthesis |
| lifespan | 1–2 years | Aquarium-literature consensus | low confidence | AquariumHQ husbandry synthesis |
| temperature | 22–26 °C | Aquarium-literature consensus | low confidence | AquariumHQ husbandry synthesis |
| ph | 6–7.5 pH | Aquarium-literature consensus | low confidence | AquariumHQ husbandry synthesis |
| general hardness | 3–12 °dGH | Aquarium-literature consensus | low confidence | AquariumHQ husbandry synthesis |
| minimum tank volume | ≥ 40 L | AquariumHQ editorial position | moderate confidence | AquariumHQ husbandry synthesis |
| minimum tank length | ≥ 50 cm | AquariumHQ editorial position | moderate confidence | AquariumHQ husbandry synthesis |
Last reviewed 2026-08-10. Values labelled as an aquarium-literature consensus are AquariumHQ editorial positions rather than measurements — see how evidence is handled.
Why we say this
What each figure on this page rests on, and how far that is from being independently established.
Every figure on this page has a provenance. Open any claim to see what AquariumHQ holds for it, which sources say what, and what a claim of that kind actually needs. Different claims need different evidence: an accepted scientific name is settled by one authority, while a legal restriction needs a current primary instrument. A single source is often the right answer rather than a thin one.
scientific nameAquariumHQ's own position, externally checkableBased on a verified authoritative source.
AquariumHQ's own position on a claim an external source could support.
What this kind of claim needs: accepted scientific name and classification — 1 authoritative source in an appropriate context. Checked against gbif on 2026-08-12. One authoritative backbone is what this class requires.
What would improve this: Go and read a source. This is reachable and has not been reached.
native rangeAquariumHQ's own position, externally checkableBased on a verified authoritative source.
AquariumHQ's own position on a claim an external source could support.
What this kind of claim needs: where the species occurs — 1 authoritative source in an appropriate context. 6 distribution statements held from GBIF checklists — native in 3 country. Establishment means is reproduced from the source, never inferred from occurrence.
What would improve this: Go and read a source. This is reachable and has not been reached.
adult sizeAquariumHQ's own position, externally checkableAquariumHQ's own position, derived from evidenced inputs.
AquariumHQ's own position on a claim an external source could support.
What this kind of claim needs: size a well-kept specimen reaches — no external source is required, provided AquariumHQ shows its reasoning. No external source is required for this class. AquariumHQ's position stands on its stated reasoning.
What would improve this: Go and read a source. This is reachable and has not been reached.
lifespanAquariumHQ's own position, externally checkableAquariumHQ's own position, derived from evidenced inputs.
AquariumHQ's own position on a claim an external source could support.
What this kind of claim needs: what aquariumhq advises for keeping — no external source is required, provided AquariumHQ shows its reasoning. No external source is required for this class. AquariumHQ's position stands on its stated reasoning.
What would improve this: Go and read a source. This is reachable and has not been reached.
temperatureAquariumHQ's own position, externally checkableAquariumHQ's own position, derived from evidenced inputs.
AquariumHQ's own position on a claim an external source could support.
What this kind of claim needs: what aquariumhq advises for keeping — no external source is required, provided AquariumHQ shows its reasoning. No external source is required for this class. AquariumHQ's position stands on its stated reasoning.
What would improve this: Go and read a source. This is reachable and has not been reached.
phAquariumHQ's own position, externally checkableAquariumHQ's own position, derived from evidenced inputs.
AquariumHQ's own position on a claim an external source could support.
What this kind of claim needs: what aquariumhq advises for keeping — no external source is required, provided AquariumHQ shows its reasoning. No external source is required for this class. AquariumHQ's position stands on its stated reasoning.
What would improve this: Go and read a source. This is reachable and has not been reached.
general hardnessAquariumHQ's own position, externally checkableAquariumHQ's own position, derived from evidenced inputs.
AquariumHQ's own position on a claim an external source could support.
What this kind of claim needs: what aquariumhq advises for keeping — no external source is required, provided AquariumHQ shows its reasoning. No external source is required for this class. AquariumHQ's position stands on its stated reasoning.
What would improve this: Go and read a source. This is reachable and has not been reached.
minimum tank volumeAquariumHQ's judgement — no authority publishes thisAquariumHQ's own position, derived from evidenced inputs.
No external authority publishes this. The rationale carries the reasoning.
What this kind of claim needs: minimum tank size — no external source is required, provided AquariumHQ shows its reasoning. No authority publishes this. AquariumHQ derives it, and the derivation is recorded with its inputs and assumptions.
What would improve this: Keep the rationale current. There is no source to find.
minimum tank lengthAquariumHQ's judgement — no authority publishes thisAquariumHQ's own position, derived from evidenced inputs.
No external authority publishes this. The rationale carries the reasoning.
What this kind of claim needs: minimum tank size — no external source is required, provided AquariumHQ shows its reasoning. No authority publishes this. AquariumHQ derives it, and the derivation is recorded with its inputs and assumptions.
What would improve this: Keep the rationale current. There is no source to find.
Group size and social behaviour
Males are intolerant of each other and display almost constantly. Kept as one male with females, or in a tank long enough to hold two territories.