Blue gularis
The largest killifish most keepers will meet and the most spectacular, with a trident-shaped tail on adult males. It is a semi-annual species — the eggs will take a dry period but do not always need one — and a genuine predator at 12 cm.
Quick profile
- Scientific name
- Fundulopanchax sjostedti
- Adult size
- 10–13 cm (3.9–5.1 in)
- Lifespan
- 2–3 years
- Temperature
- 22–26 °C (72–79 °F)
- pH
- 5.5–7
- Hardness
- 1–8 °dGH
- Minimum tank
- 90 L (24 US gal)
- Minimum length
- 75 cm
- Swimming zone
- Bottom
- Social
- Pair
- Diet
- Carnivore
- Overall confidence
- low confidence
What keeping this species involves
Very soft acidic water, large live foods, males kept apart and a covered tank. It is not fragile; it is particular.
Seasonal swamp pools and slow forest channels in very soft acidic water.
Identity and names
- Common name
- Blue gularis
- Scientific name
- Fundulopanchax sjostedti
- Family
- Nothobranchiidae
- Order
- Cyprinodontiformes
- Class
- Actinopterygii
- Also sold as
- Fundulopanchax sjoestedti, Aphyosemion sjoestedti, golden pheasant killifish
- Former or synonymous names
- Fundulopanchax sjoestedti, Aphyosemion sjoestedti
Name ambiguity
Sold universally as Fundulopanchax sjoestedti. The accepted spelling has no first 'e' — sjostedti — and the trade version is a synonym of it.
Adult size and growth
10–13 cm (3.9–5.1 in)
Typical lifespan in an aquarium: 2–3 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.
Shape, which is what the compatibility engine reads instead of length alone: fusiform — the ordinary torpedo with a moderate. Assigned from what is typical of Nothobranchiidae, not examined for this species.
Water and tank requirements
A 12 cm predator that holds a floor territory needs a footprint that contains it and leaves the female somewhere else to be.
Temperature (°C)
Scale: 0 to 36 °C.
pH (pH)
Scale: 4 to 9.5 pH.
Hardness (°dGH)
Scale: 0 to 30 °dGH.
Where these figures come from
Habitat class
Seasonal pool
Water that exists for part of the year and dries completely for the rest — the habitat of the annual killifishes.
The chemistry is the least important thing about this habitat. What matters is that the animal's whole life is compressed into months, and a keeper who slows that down with cool, stable water is often doing the fish a favour.
- Conductivity
- 30–400 µS/cm
- Flow
- still
- Dissolved oxygen
- variable
- Seasonality
- strong
These are figures for the KIND of water body, not measurements of this species. They are AquariumHQ’s summary of the general limnology and are given wide because the water is.
- TemperatureFollows the habitat this animal comes from
- Follows the water this animal is recorded from — seasonal pool. Seasonal pool generally runs 18–34°C, and the advised band of 22–26°C is consistent with it. This is AquariumHQ's reasoning from the habitat, not a measurement of the species.
- pHFollows the habitat this animal comes from
- Follows the water this animal is recorded from — seasonal pool. Seasonal pool generally runs 5.5–7.5, and the advised band of 5.5–7 is consistent with it. This is AquariumHQ's reasoning from the habitat, not a measurement of the species.
- General hardnessFollows the habitat this animal comes from
- Follows the water this animal is recorded from — seasonal pool. Seasonal pool generally runs 1–12 dGH, and the advised band of 1–8 dGH is consistent with it. This is AquariumHQ's reasoning from the habitat, not a measurement of the species.
Scale: 15.6 to 36.4 °C.
Scale: 5.2 to 7.8 pH.
Scale: -0.6 to 13.7 dGH.
| Requirement | Value | Notes |
|---|---|---|
| Temperature | 22–26 °C (72–79 °F) | Stability matters more than hitting an exact figure. |
| pH | 5.5–7 | A stable pH outside the ideal band is usually better than an unstable one inside it. |
| General hardness | 1–8 °dGH | Check your supplier's published figure before choosing species. |
| Minimum volume | 90 L (24 US gal) | A floor, not a recommendation. |
| Minimum footprint | 75 cm long | A 12 cm predator that holds a floor territory needs a footprint that contains it and leaves the female somewhere else to be. |
| Water flow | still | Match the outflow to this rather than to the filter's rating. |
| Lid required | Yes | This species jumps. |
| Structure | Peat or dark substrate, dense planting and shade. Bright bare tanks wash it out entirely. |
Behaviour
- Sits low and still, then moves suddenly over short distances.
- Males display along a boundary with the caudal lobes fully spread.
Telling males from females
Males develop the three-lobed caudal and heavy red-blue patterning. Females are plain brown with rounded fins.
Feeding
Large live and frozen foods. Dry food is generally refused by adults.
- Diet type
- Carnivore
- Staples
- Live and frozen bloodworm, Live earthworm and blackworm, Frozen krill and mysis
Breeding
- Strategy
- Egg-burying in peat, hatching wet or after a short dry period
- Difficulty
- challenging
- Parental care
- none
Semi-annual: eggs from one spawning can hatch on different schedules, which spreads the risk in a habitat that does not dry out predictably.
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 | near-certain | Anything that fits in the mouth is at risk once this species reaches adult size. |
| Adult dwarf shrimp | near-certain | Cover reduces losses but rarely prevents them where the risk is high. |
| Shrimplets | near-certain | Determines whether a shrimp colony can grow rather than merely persist. |
| Snails | low | 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.
- A community fish only among tankmates too large to swallow, which at 12 cm rules out most of the catalogue.
- Sold under a misspelling that does not resolve against the authority. Both spellings are searchable here.
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 swamp forest of southern Nigeria and western Cameroon
- Habitat
- Seasonal swamp pools and slow forest channels in very soft acidic water.
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 | Fundulopanchax sjostedti | Observed / measured | high confidence | Catalogue of Life; GBIF — Global Biodiversity Information Facility |
| native range | Coastal swamp forest of southern Nigeria and western Cameroon | Observed / measured | moderate confidence | GBIF — Global Biodiversity Information Facility |
| adult size | 10–13 cm | Aquarium-literature consensus | low confidence | AquariumHQ husbandry synthesis |
| lifespan | 2–3 years | Aquarium-literature consensus | low confidence | AquariumHQ husbandry synthesis |
| temperature | 22–26 °C | Aquarium-literature consensus | low confidence | AquariumHQ husbandry synthesis |
| ph | 5.5–7 pH | Aquarium-literature consensus | low confidence | AquariumHQ husbandry synthesis |
| general hardness | 1–8 °dGH | Aquarium-literature consensus | low confidence | AquariumHQ husbandry synthesis |
| minimum tank volume | ≥ 90 L | AquariumHQ editorial position | moderate confidence | AquariumHQ husbandry synthesis |
| minimum tank length | ≥ 75 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, and the source files it under "Fundulopanchax sjostedti" — both names are searchable.
What would improve this: Go and read a source. This is reachable and has not been reached.
native rangeAquariumHQ's own position, externally checkableLimited evidence — treat with caution.
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. No checklist distribution statement is held for this species. The range on the page is editorial until one is.
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.
Guides relevant to this species
Chosen from this record's own traits rather than listed on every page.
- Predator and prey sizeIt takes fish that fit in its mouth, and its mouth grows with it.
- Scientific and trade namesThis species has been published under more than one accepted name.
- The kinds of water aquarium fish come fromThis record's water bands follow seasonal pool, which is the kind of water this animal is recorded from.
Group size and social behaviour
Kept as a pair or one male with two females. Males are aggressive to each other and will not share a small tank.