Altum angelfish
The tallest of the angelfish, reaching around forty centimetres from dorsal tip to anal tip in a body only fifteen long. It is a blackwater specialist, mostly wild-caught, and it is not a larger version of the common angelfish in anything except outline.
Quick profile
- Scientific name
- Pterophyllum altum
- Adult size
- 13–18 cm (5.1–7.1 in)
- Lifespan
- 8–12 years
- Temperature
- 27–31 °C (81–88 °F)
- pH
- 4.5–6
- Hardness
- 0–3 °dGH
- Minimum tank
- 400 L (106 US gal)
- Minimum length
- 120 cm
- Swimming zone
- Midwater
- Social
- Shoaling — at least 5
- Diet
- Omnivore
- Overall confidence
- moderate confidence
What keeping this species involves
Water chemistry it will not compromise on, a tank height very few aquaria have, and stock that is usually wild-caught and arrives stressed. Each of those alone would make it demanding.
Deep, slow blackwater channels among flooded root systems, in water stained dark and almost devoid of dissolved minerals.
Identity and names
- Common name
- Altum angelfish
- Scientific name
- Pterophyllum altum
- Family
- Cichlidae
- Order
- Cichliformes
- Class
- Actinopterygii
- Also sold as
- Pterophyllum altum, orinoco angelfish, deep angelfish, altum
Adult size and growth
13–18 cm (5.1–7.1 in) — Body length. The measurement that decides the tank is the vertical span, which reaches 35–40 cm in a mature fish and is why standard-height aquaria do not suit it.
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: disc — as deep as it is long with a moderate. Deeper again than P. scalare.
Water and tank requirements
The constraint here is height rather than length: a fish spanning close to forty centimetres vertically cannot orient normally in a standard sixty-centimetre-tall aquarium. A tall tank is the requirement and the volume follows from it.
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: Upper Orinoco blackwater is warm, extremely soft and genuinely acidic — conductivity in the collection areas is very low, and this species is one of the few aquarium fish for which that is a requirement rather than a preference. Wild-caught stock kept at neutral pH and moderate hardness is the commonest reason imports fail.
Where these figures come from
Habitat class
Blackwater — the upper Orinoco and Rio Negro headwaters
Tannin-stained water draining podzolic forest sand, carrying almost no dissolved mineral and a heavy load of humic and fulvic acid.
The defining property is the absence of mineral, not the colour. Water this soft has almost no buffering, so pH moves fast and a keeper's job is stability rather than chasing the wild figure.
- Conductivity
- 8–40 µS/cm
- Flow
- low
- Dissolved oxygen
- moderate
- 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 | 27–31 °C (81–88 °F) | Stability matters more than hitting an exact figure. |
| pH | 4.5–6 | A stable pH outside the ideal band is usually better than an unstable one inside it. |
| General hardness | 0–3 °dGH | Check your supplier's published figure before choosing species. |
| Minimum volume | 400 L (106 US gal) | A floor, not a recommendation. |
| Minimum footprint | 120 cm long × 50 cm deep | The constraint here is height rather than length: a fish spanning close to forty centimetres vertically cannot orient normally in a standard sixty-centimetre-tall aquarium. A tall tank is the requirement and the volume follows from it. |
| Water flow | low | Match the outflow to this rather than to the filter's rating. |
| Lid required | Recommended | Reduces evaporation and prevents accidents. |
| Structure | Tall vertical wood and leaf litter, arranged to leave open water between. Botanicals both stain the water and help hold the chemistry. |
Behaviour
- Holds position among vertical structure and moves between root columns rather than crossing open water.
- Startles hard and vertically, which in a tank without enough height means striking the surface or the glass.
Telling males from females
Not readable outside spawning. Sexing is by the breeding tube, which is visible only in fish that are about to spawn.
Feeding
Wild imports often refuse dry food for weeks and take live or frozen readily. Getting a new import feeding at all is the first task and it can take time.
- Diet type
- Omnivore
- Staples
- Frozen bloodworm, Frozen mysis, Live blackworm, Quality flake
Breeding
- Strategy
- Adhesive eggs on a vertical surface, guarded by both parents
- Difficulty
- rarely achieved
- Parental care
- guarding
Very few aquarium spawnings succeed. The eggs are reported to require extremely soft acidic water to develop, which is also the hardest condition to hold stable.
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 | high | 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 | 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.
- Almost all stock is wild-caught. Losses in the first weeks are high and are largely a function of transport and of being put straight into hard neutral water.
- Hybrids with the common angelfish are sold as altum and are intermediate in both requirements and appearance. A genuine altum is expensive and a cheap one is usually not what it says.
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
- The upper Orinoco and the Rio Negro headwaters — Venezuela, Colombia and Brazil
- Habitat
- Deep, slow blackwater channels among flooded root systems, in water stained dark and almost devoid of dissolved minerals.
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 |
|---|---|---|
| Native | 1 | A checklist states the species occurs here naturally. |
| Recorded as present, establishment means not stated | 6 | 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 | Pterophyllum altum | Observed / measured | high confidence | Catalogue of Life; GBIF — Global Biodiversity Information Facility |
| native range | The upper Orinoco and the Rio Negro headwaters — Venezuela, Colombia and Brazil | Observed / measured | moderate confidence | GBIF — Global Biodiversity Information Facility |
| adult size | 13–18 cm | Aquarium-literature consensus | moderate confidence | AquariumHQ husbandry synthesis |
| lifespan | 8–12 years | Aquarium-literature consensus | moderate confidence | AquariumHQ husbandry synthesis |
| temperature | 27–31 °C | Aquarium-literature consensus | moderate confidence | AquariumHQ husbandry synthesis |
| ph | 4.5–6 pH | Aquarium-literature consensus | moderate confidence | AquariumHQ husbandry synthesis |
| general hardness | 0–3 °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 | ≥ 120 cm | AquariumHQ editorial position | moderate confidence | AquariumHQ husbandry synthesis |
| minimum group size | ≥ 5 | 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 — native in 1 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.
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.
- 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.
- Wild conditions and aquarium recommendationsThe water band on this page is an AquariumHQ position with a stated reason, not a measurement of a river.
- How to read a compatibility verdictThis animal's fins are a target, and most compatibility verdicts about that are derived rather than observed.
Group size and social behaviour
Grows on in a group and pairs off from within it, in the same way as the common angelfish. Unpaired adults need somewhere to go once a pair forms.