Leopold's angelfish
The smallest angelfish and by a wide margin the most aggressive, distinguished by a dark blotch high on the body that the other two species do not carry. It is regularly imported by accident among common angelfish and behaves nothing like them.
Quick profile
- Scientific name
- Pterophyllum leopoldi
- Adult size
- 8–11 cm (3.1–4.3 in)
- Lifespan
- 6–10 years
- Temperature
- 26–30 °C (79–86 °F)
- pH
- 5–6.8
- Hardness
- 1–6 °dGH
- Minimum tank
- 200 L (53 US gal)
- Minimum length
- 100 cm
- Swimming zone
- Midwater
- Social
- Pair
- Diet
- Omnivore
- Overall confidence
- moderate confidence
What keeping this species involves
Soft acidic water, a small mouth that needs appropriate food, and a temperament that rules out the community tank its shape suggests.
River margins and floodplain lakes among submerged wood, in clear and black waters of the central Amazon.
Identity and names
- Common name
- Leopold's angelfish
- Scientific name
- Pterophyllum leopoldi
- Family
- Cichlidae
- Order
- Cichliformes
- Class
- Actinopterygii
- Also sold as
- Pterophyllum leopoldi, dwarf angel cichlid, teardrop angelfish, leopoldi
Adult size and growth
8–11 cm (3.1–4.3 in)
Typical lifespan in an aquarium: 6–10 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. The same disc outline in a smaller fish.
Water and tank requirements
A small angelfish that is unusually intolerant of its own kind. The area is what allows a second fish to be somewhere the first is not.
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: Amazonian clear and black waters, soft and acidic but less extreme than the upper Orinoco. The species is more tolerant than the altum and less so than the common angelfish.
Where these figures come from
Habitat class
Soft-water lake
Standing water with very low dissolved mineral — Lake Mai-Ndombe, Lake Inle's softer reaches, forest lakes and blackwater lagoons.
Blackwater chemistry without blackwater current. Species from here generally want the softness and specifically do not want flow.
- Conductivity
- 10–80 µS/cm
- Flow
- still
- Dissolved oxygen
- moderate
- Seasonality
- moderate
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 | 26–30 °C (79–86 °F) | Stability matters more than hitting an exact figure. |
| pH | 5–6.8 | A stable pH outside the ideal band is usually better than an unstable one inside it. |
| General hardness | 1–6 °dGH | Check your supplier's published figure before choosing species. |
| Minimum volume | 200 L (53 US gal) | A floor, not a recommendation. |
| Minimum footprint | 100 cm long × 40 cm deep | A small angelfish that is unusually intolerant of its own kind. The area is what allows a second fish to be somewhere the first is not. |
| Water flow | low | Match the outflow to this rather than to the filter's rating. |
| Lid required | Recommended | Reduces evaporation and prevents accidents. |
| Structure | Vertical wood with open water between, and leaf litter on the floor. Broken sight lines matter more here than for the other angelfish. |
Behaviour
- Defends a chosen piece of wood against other angelfish continuously rather than seasonally.
- Hangs among vertical structure with the body tilted, using the barring as disruptive camouflage against the wood.
Telling males from females
No reliable external difference outside spawning.
Feeding
Takes insect larvae and small crustaceans among wood. It feeds in short deliberate strikes rather than grazing and is easily out-competed by faster fish.
- Diet type
- Omnivore
- Staples
- Frozen bloodworm, Frozen brine shrimp, Live blackworm, Small sinking pellets
Breeding
- Strategy
- Adhesive eggs on a vertical surface, guarded by both parents
- Difficulty
- challenging
- 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 | 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.
- Frequently mixed into shipments of common angelfish and sold as one. A keeper who bought six angelfish and found one that will not stop fighting has probably found this species.
- The smallest angelfish is still a cichlid with a mouth that fits a neon tetra, and its size gets it recommended for tanks where it will demonstrate that.
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 Amazon mainstream, the lower Rio Negro and the Solimões — Brazil and Peru
- Habitat
- River margins and floodplain lakes among submerged wood, in clear and black waters of the central Amazon.
What the checklists say
5 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 | 2 | 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 | Pterophyllum leopoldi | Observed / measured | high confidence | Catalogue of Life; GBIF — Global Biodiversity Information Facility |
| native range | The Amazon mainstream, the lower Rio Negro and the Solimões — Brazil and Peru | Observed / measured | moderate confidence | GBIF — Global Biodiversity Information Facility |
| adult size | 8–11 cm | Aquarium-literature consensus | moderate confidence | AquariumHQ husbandry synthesis |
| lifespan | 6–10 years | Aquarium-literature consensus | moderate confidence | AquariumHQ husbandry synthesis |
| temperature | 26–30 °C | Aquarium-literature consensus | moderate confidence | AquariumHQ husbandry synthesis |
| ph | 5–6.8 pH | Aquarium-literature consensus | moderate confidence | AquariumHQ husbandry synthesis |
| general hardness | 1–6 °dGH | Aquarium-literature consensus | moderate confidence | AquariumHQ husbandry synthesis |
| minimum tank volume | ≥ 200 L | AquariumHQ editorial position | moderate confidence | AquariumHQ husbandry synthesis |
| minimum tank length | ≥ 100 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. 5 distribution statements held from GBIF checklists — native in 2 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.
- 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
Considerably less sociable than the common angelfish. Groups of adults fight persistently, and a bonded pair in a tank of its own is the arrangement that works.