Green terror
A heavily built cichlid patterned in metallic green and blue, with a name that is half accurate — it is genuinely territorial and it is not uniformly hostile. Adults reach twenty-five centimetres and the fish sold at four is often the wrong species entirely.
Quick profile
- Scientific name
- Andinoacara rivulatus
- Adult size
- 20–25 cm (7.9–9.8 in)
- Lifespan
- 8–12 years
- Temperature
- 20–26 °C (68–79 °F)
- pH
- 6.5–8
- Hardness
- 5–20 °dGH
- Minimum tank
- 400 L (106 US gal)
- Minimum length
- 150 cm
- Swimming zone
- All levels
- Social
- Pair
- Diet
- Carnivore
- Overall confidence
- moderate confidence
What keeping this species involves
Hardy, adaptable and easy to feed. The requirements are space, a cooler tank than most people run, and tankmates chosen on size rather than on temperament.
Coastal rivers and streams on the western side of the Andes, in moderately hard water that is cooler than most South American cichlid habitat.
Identity and names
- Common name
- Green terror
- Scientific name
- Andinoacara rivulatus
- Family
- Cichlidae
- Order
- Cichliformes
- Class
- Actinopterygii
- Also sold as
- Andinoacara rivulatus, Aequidens rivulatus, gold saum, silver saum
- Former or synonymous names
- Aequidens rivulatus
Adult size and growth
20–25 cm (7.9–9.8 in)
Typical lifespan in an aquarium: 8–12 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: deep-bodied with a moderate. Assigned from what is typical of Cichlidae, not examined for this species.
Water and tank requirements
A twenty-five-centimetre cichlid that claims ground and pursues across it. The length is set by how far a displaced tankmate needs to be able to get.
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: Pacific-slope Ecuadorian rivers run cooler than the Amazon lowlands, and this species is found in water in the low twenties. Keeping it at typical tropical community temperature shortens its life without producing any obvious symptom.
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 | 6.5–8 | A stable pH outside the ideal band is usually better than an unstable one inside it. |
| General hardness | 5–20 °dGH | Check your supplier's published figure before choosing species. |
| Minimum volume | 400 L (106 US gal) | A floor, not a recommendation. |
| Minimum footprint | 150 cm long × 50 cm deep | A twenty-five-centimetre cichlid that claims ground and pursues across it. The length is set by how far a displaced tankmate needs to be able to get. |
| Water flow | moderate | Match the outflow to this rather than to the filter's rating. |
| Lid required | Recommended | Reduces evaporation and prevents accidents. |
| Structure | Rock, wood and open sand. Anything planted will be dug up, and rockwork has to be stable because the fish will excavate under it. |
Behaviour
- Rearranges the substrate constantly, moving sand into ridges and undermining anything resting on it.
- Displays laterally with the gill covers flared before any actual contact, and most disputes end there when there is room for one fish to withdraw.
Telling males from females
Males grow larger, develop a pronounced nuchal hump and have longer fin extensions. The white or orange band on the tail edge distinguishes the two trade forms and not the sexes.
Feeding
Takes invertebrates and small fish in the wild and accepts a good pellet readily. Mammalian meat is poorly digested and is a recurring cause of intestinal problems in large cichlids.
- Diet type
- Carnivore
- Staples
- Sinking cichlid pellets, Frozen krill, Earthworm, Frozen mysis
- Avoid
- Mammalian meat, Live feeder fish
Breeding
- Strategy
- Adhesive eggs on a cleaned flat surface, guarded by both parents
- Difficulty
- straightforward
- Parental care
- guarding
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 | occasional | Fin damage is an entry point for secondary infection. |
| Plants | uproots | Tough species such as Anubias and Java fern survive most grazers. |
Assessed pairings
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.
- Frequently confused in the trade with the blue acara, which stays half the size and is a far more moderate fish. A shop label reading 'acara' does not settle which of the two is in the bag.
- A pair that spawns will hold most of an ordinary tank. Planning for that before the eggs appear is the difference between a managed situation and an emergency.
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
- Pacific slope drainages of western Ecuador and northern Peru
- Habitat
- Coastal rivers and streams on the western side of the Andes, in moderately hard water that is cooler than most South American cichlid habitat.
What the checklists say
7 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 |
|---|---|---|
| Introduced | 5 | 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 | 2 | The source records the species as present and does not say whether it is native or introduced. AquariumHQ does not fill that in. |
No checklist AquariumHQ holds positively calls this species native anywhere, so the native range above rests on AquariumHQ’s own reading of the literature rather than on a cited checklist.
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 | Andinoacara rivulatus | Observed / measured | high confidence | Catalogue of Life; GBIF — Global Biodiversity Information Facility |
| native range | Pacific slope drainages of western Ecuador and northern Peru | Observed / measured | moderate confidence | GBIF — Global Biodiversity Information Facility |
| adult size | 20–25 cm | Aquarium-literature consensus | moderate confidence | AquariumHQ husbandry synthesis |
| lifespan | 8–12 years | Aquarium-literature consensus | moderate confidence | AquariumHQ husbandry synthesis |
| temperature | 20–26 °C | Aquarium-literature consensus | moderate confidence | AquariumHQ husbandry synthesis |
| ph | 6.5–8 pH | Aquarium-literature consensus | moderate confidence | AquariumHQ husbandry synthesis |
| general hardness | 5–20 °dGH | Aquarium-literature consensus | moderate confidence | AquariumHQ husbandry synthesis |
| minimum tank volume | ≥ 400 L | AquariumHQ editorial position | moderate confidence | AquariumHQ husbandry synthesis |
| minimum tank length | ≥ 150 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 2026-08-29. 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. 7 distribution statements held from GBIF checklists — introduced in 5 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.
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.
- Territorial behaviourIt defends ground, and the shape of what it defends decides the tank more than the volume does.
- Scientific and trade namesThis species has been published under more than one accepted name.
- Wild conditions and aquarium recommendationsThe water band on this page is an AquariumHQ position with a stated reason, not a measurement of a river.
- Rehoming an animal you can no longer keepThis animal reaches 25 cm. Most of the difficult rehoming cases are fish sold small that were always going to become impossible.
- How to read a compatibility verdictThis animal is recorded as nipping fins, which is one of the few compatibility factors with real reports behind it.
Group size and social behaviour
Pairs form and hold ground together. Two unpaired adults in one tank is a fight, and a pair that has not bonded is a fight with a delay.