Care guide · Freshwater · fish

Freshwater angelfish

Pterophyllum scalare

Photo: Versions111 · Source · CC BY 4.0Resized and compressed; no cropping or colour changes.

An angelfish may look like a modest juvenile in a shop, but develops into a tall cichlid with extended fins and territorial behaviour. Pterophyllum scalare moves among vertical roots and plants and can eat small fish when adult. Its graceful swimming is therefore no proof that it belongs with every tetra. This Amazonian species primarily needs a large, tall, carefully structured aquarium. For ordinary group maintenance, plan at least six individuals with ample space and a way to intervene when pairs form. An arbitrary duo is not a safe substitute for social planning. Before purchase, assess adult height, floor area, group dynamics and companions. Starting with a small tank because young fish fit temporarily is the central mistake to avoid.

Plan your aquarium →

At a glance

Temperature: 24–28 °C
pH: 6.0–7.0
GH: 3–12 °dGH
Aquarium length: At least 120 cm
Minimum aquarium volume: At least 360 L
Adult size: Approximately 15 cm
Group size: At least 6 individuals
Swimming zone: Middle
Temperament: Territorial, Predator
Lighting preference: Subdued lighting
Cover: Plants and sheltered areas
Staple food: Fine flakes
Supplementary food: Live food, Frozen food, Finely crumbled dried natural food

Group maintenance requires at least 120 cm length and 50 cm tank height. Our preferred starting plan is at least 120 × 50 × 60 cm, approximately 360 litres gross, with 150 cm and around 450 litres or more preferable. This volume recommendation describes a spacious layout for six fish, not an exact biological minimum or a guarantee of peaceful pairs.

About this species

Adults reach around 15 cm in body length and can exceed 20 cm in height including fins. Long-finned forms require additional clear height and safe decor. The laterally compressed body is characteristic; Pterophyllum altum and other relatives should not automatically receive identical care advice. The photograph shows a captive P. scalare form, not a verified wild locality variant.

Gold, marble and other colour patterns do not remove predatory or territorial behaviour. Sex is often difficult to establish reliably outside breeding, and fin shape alone is insufficient. Choose well-built fish without damaged fins or hollow bellies, and plan their final accommodation when purchasing juveniles.

Natural habitat

The species occurs across parts of the Amazon region in South America. Quiet river sections, sheltered margins and flooded structures provide vertical roots, branches and vegetation through which the tall body can manoeuvre. Conditions differ among populations, and an ornamental strain does not represent one specific locality. Aquarium priorities are height, broken sightlines and clear routes.

Use tall structures without reducing the tank to narrow crevices. Retain calm areas alongside effective gas exchange. Naturally dark or stained surroundings do not justify neglected maintenance. A group of large fish produces enough waste to require a deliberate filtration and water-change routine, rather than relying on the appearance of a natural layout.

Aquarium and layout

Low Cryptocoryne offers bottom cover but cannot replace tall structure. Use mature filtration, a lid and gentle output. Keep a separation option available for persistent aggression.

Water conditions

For daily care choose 24–28 °C, pH 6–7 and approximately 3–12 °dGH. Soft-water guidance mentions KH below about 4 °dKH; this requires stable preparation and monitoring rather than sudden acid dosing. Wild fish may have more specific requirements than ordinary captive forms.

Ammonia and nitrite should be undetectable. Regularly replace enough matched water for the group’s actual load and verify temperature with a thermometer. A tall tank and large volume cannot prevent local oxygen problems when filtration or maintenance is inadequate.

Behaviour and group size

Plan at least six for ordinary group keeping. Pairs may emerge and defend areas, sometimes placing serious pressure on the remaining fish. An established breeding pair in separate suitable accommodation is different from randomly keeping two fish together. Watch for individuals confined behind equipment or excluded from meals.

Small tetras and pygmy corys face predation, even if ignored when the angelfish were young. Long-finned bettas are also a poor choice. Assess larger companions through adult size and available space, and never treat a favourable card as a guarantee against individual behaviour.

Feeding

Use a complete tropical omnivore food containing suitable animal ingredients. Flakes or granules must fit the current mouth size: juveniles need finer particles than adults. Offer one or two controlled daily meals and ensure subordinate fish also eat. Small live or thawed invertebrates provide variety.

Dried Daphnia is a modest supplement, not a sufficient staple for this larger fish. Feeder fish are unnecessary. Use several feeding points if dominant individuals monopolise food, but do not attempt to solve persistent bullying by feeding more. Remove leftovers and avoid overloading filtration and water quality.

Breeding

An established pair may lay eggs on a vertical leaf, stone or wooden surface. Both parents can tend and defend the brood, reducing neighbours’ access to the territory. An initial clutch may be lost without requiring immediate intervention. A separate spacious, tall breeding setup is easier to manage than a busy community.

Once yolk is exhausted, free-swimming fry need suitably fine food, such as appropriate Artemia nauplii. Prepare adequate growing space: numerous young quickly create a substantial load. Reliable housing and destinations for offspring should precede encouraging further spawning.