Pterophyllum scalare: living card for the freshwater angelfish

Pterophyllum scalare (freshwater angelfish) is sold small, then grows tall, forms pairs, and may eat fish that fit in its mouth.

Quick read

• Type: tall, territorial South American cichlid.
• Aquarium: tall, mature, with vertical wood and broad zones.
• Indicative temperature: 25-28 C.
• pH: 6.0-7.4.
• Hardness: soft to moderate.
• Base volume: 180 L or more for a young group or adult pair.
• Feeding: omnivorous with quality protein and controlled portions.
• Difficulty: medium; adult size changes everything.

What to check before buying

Choose symmetrical fish with complete fins and stable vertical swimming. Avoid bent spines or heavily eroded fins.

Before buying, confirm that the aquarium is cycled, the group size or pair plan makes sense, and the setup runs at the species’ real temperature.

Aquarium design

The aquarium needs height and vertical structure. Robust plants, roots, and retreat routes reduce conflict when a pair defends an area.

Use the card as a baseline, then watch the fish. Loss of colour, constant hiding, or all-day competition calls for a design correction before a chemical fix.

Working parameters

It tolerates more than a ram, but it is not a dirty-water fish. Keep nitrate low, temperature stable, and water changes predictable.

Treat these ranges as a working zone, not permission to swing parameters. Rapid changes, immature aquariums, and incompatible species cause most problems.

Compatibility and warning

Do not mix with adult neons unless predation risk is accepted, and avoid fin nippers. Calm, medium-sized, non-territorial tankmates are safer.

Constant chasing, bitten fins, or missing small fish are not accidents: they signal poor compatibility planning.

Reference sources

FishBase for taxonomy and distribution; NOAA/University of Florida historical ornamental-trade data for frequent market species; Aquarium Co-Op and specialist aquarium guides for practical husbandry ranges.