Flame tetra
A small red-tailed tetra from the coastal streams around Rio de Janeiro, subtropical rather than tropical, and one of the older species in the hobby. Its native habitat has been substantially urbanised and the aquarium population is now considerably more secure than the wild one.
Quick profile
- Scientific name
- Hyphessobrycon flammeus
- Adult size
- 3–4 cm (1.2–1.6 in)
- Lifespan
- 3–5 years
- Temperature
- 20–26 °C (68–79 °F)
- pH
- 5.5–7.5
- Hardness
- 2–12 °dGH
- Minimum tank
- 45 L (12 US gal)
- Minimum length
- 50 cm
- Swimming zone
- Midwater
- Social
- Shoaling — at least 8
- Diet
- Micropredator
- Overall confidence
- moderate confidence
What keeping this species involves
Hardy, tolerant of cool water, easy to feed and easy to breed. One of the genuinely straightforward small characins.
Small coastal streams and pools in the Atlantic forest, cooler than Amazonian water and often heavily vegetated.
Identity and names
- Common name
- Flame tetra
- Scientific name
- Hyphessobrycon flammeus
- Family
- Characidae
- Order
- Characiformes
- Class
- Actinopterygii
- Also sold as
- Hyphessobrycon flammeus, von Rio tetra, red tetra, Rio tetra
Adult size and growth
3–4 cm (1.2–1.6 in)
Typical lifespan in an aquarium: 3–5 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 small terminal mouth. Assigned from what is typical of Characidae, not examined for this species.
Water and tank requirements
A small shoaling tetra in a planted tank. The length lets the shoal move together rather than mill in a corner.
Temperature (°C)
Scale: 0 to 36 °C.
pH (pH)
Scale: 4 to 9.5 pH.
Hardness (°dGH)
Scale: 0 to 30 °dGH.
Why these ranges: Atlantic-forest coastal streams around Rio de Janeiro experience a genuine cool season, and this species is found across a lower temperature range than the Amazonian tetras. The band is set from that rather than from general tetra practice.
Where these figures come from
Habitat class
Subtropical stream
Running water at the margins of the tropics — a mild winter, a warm summer and no ice.
Species from here are usually sold as tropical and usually kept several degrees too warm all year. A cooler winter is not neglect; it is the season they evolved in.
- Conductivity
- 100–500 µS/cm
- Flow
- moderate
- Dissolved oxygen
- near saturation
- 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.
- TemperatureReasoned on this record
- This record states its own reason for this band. See the water section.
- pHReasoned on this record
- This record states its own reason for this band. See the water section.
- General hardnessReasoned on this record
- This record states its own reason for this band. See the water section.
| Requirement | Value | Notes |
|---|---|---|
| Temperature | 20–26 °C (68–79 °F) | Stability matters more than hitting an exact figure. |
| pH | 5.5–7.5 | A stable pH outside the ideal band is usually better than an unstable one inside it. |
| General hardness | 2–12 °dGH | Check your supplier's published figure before choosing species. |
| Minimum volume | 45 L (12 US gal) | A floor, not a recommendation. |
| Minimum footprint | 50 cm long × 25 cm deep | A small shoaling tetra in a planted tank. The length lets the shoal move together rather than mill in a corner. |
| Water flow | low | Match the outflow to this rather than to the filter's rating. |
| Lid required | Recommended | Reduces evaporation and prevents accidents. |
| Structure | Planting at the back and sides with open water through the middle, and a dark substrate that brings out the colour. |
Behaviour
- Males spar with fins raised in brief bouts that settle without damage.
- Colours up strongly in a group over a dark substrate and looks washed out over a pale one, which is a lighting response rather than a health signal.
Telling males from females
Males are more intensely red with a black-edged anal fin; females are paler and rounder. The difference is clear in a settled group.
Feeding
Takes small invertebrates and prepared food readily. Nothing about feeding it is difficult.
- Diet type
- Micropredator
- Staples
- Quality flake, Frozen daphnia, Frozen cyclops, Micro pellets
Breeding
- Strategy
- Eggs scattered among fine-leaved plants and abandoned
- Difficulty
- straightforward
- Parental care
- none
One of the easier tetras to spawn. Adults eat the eggs, so a separate tank with a mesh or mop is the usual method.
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 | none | Cover reduces losses but rarely prevents them where the risk is high. |
| Shrimplets | moderate | 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.
- Its wild range is small and heavily developed, and the species is of conservation concern there while being common in aquaria. Captive-bred stock is what the trade supplies.
- Tolerates room-temperature water and is usually kept warmer than it needs. Cooler keeping suits it and extends its life.
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
- Brazil — coastal drainages around Rio de Janeiro
- Habitat
- Small coastal streams and pools in the Atlantic forest, cooler than Amazonian water and often heavily vegetated.
What the checklists say
8 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 | 1 | A checklist states the species occurs here naturally. |
| Introduced | 3 | A checklist states the species arrived here with human help. That is not a statement that it is established, harmful or illegal. |
| Recorded as present, establishment means not stated | 4 | 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 | Hyphessobrycon flammeus | Observed / measured | high confidence | Catalogue of Life; GBIF — Global Biodiversity Information Facility |
| native range | Brazil — coastal drainages around Rio de Janeiro | Observed / measured | moderate confidence | GBIF — Global Biodiversity Information Facility |
| adult size | 3–4 cm | Aquarium-literature consensus | moderate confidence | AquariumHQ husbandry synthesis |
| lifespan | 3–5 years | Aquarium-literature consensus | moderate confidence | AquariumHQ husbandry synthesis |
| temperature | 20–26 °C | Aquarium-literature consensus | moderate confidence | AquariumHQ husbandry synthesis |
| ph | 5.5–7.5 pH | Aquarium-literature consensus | moderate confidence | AquariumHQ husbandry synthesis |
| general hardness | 2–12 °dGH | Aquarium-literature consensus | moderate confidence | AquariumHQ husbandry synthesis |
| minimum tank volume | ≥ 45 L | AquariumHQ editorial position | moderate confidence | AquariumHQ husbandry synthesis |
| minimum tank length | ≥ 50 cm | AquariumHQ editorial position | moderate confidence | AquariumHQ husbandry synthesis |
| minimum group size | ≥ 8 | 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 2026-08-29. 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. 8 distribution statements held from GBIF checklists — native in 1, introduced in 3 countries. 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.
minimum group sizeAquariumHQ'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: group size — 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: 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.
- Schooling and shoalingThis species is recorded as shoal, and the number it is kept in decides how it behaves.
- Wild conditions and aquarium recommendationsThe water band on this page is an AquariumHQ position with a stated reason, not a measurement of a river.
Group size and social behaviour
Shoals loosely and males display at each other constantly, which is what produces the red. A group with several males is a better-looking group.