Pterophyllum scalare

A Little More Information...

Pterophyllum scalare, also called Amapa Red Back, is a cultivated form of the South American angelfish, valued for its tall body and elegant fins. Its coloration usually emphasizes a warm-toned back while retaining the characteristic profile of Pterophyllum scalare. This variety remains fairly common in the aquarium trade. Like other angelfish, it needs a tall aquarium, stable water and carefully selected tank mates. Raising juveniles in a group often allows adults to form pairs naturally, although territorial behavior becomes stronger during spawning. A well-planned setup helps preserve both its appearance and its calm, deliberate swimming style.

General species description

Pterophyllum scalare is a South American cichlid commonly known as an angelfish. The species has a laterally compressed body, greatly extended dorsal and anal fins, and a slow, precise, mostly vertical swimming style. The Amapa Red Back is an aquarium strain of Pterophyllum scalare, not a separate species. It is considered very common in the aquarium hobby. A spacious, tall aquarium is preferable because the total height can become considerable once the fins are fully developed. Adults may defend an area, especially after pairing. Efficient filtration, moderate water movement and clean water support long-term maintenance. Very small, slender fish may be viewed as potential prey by adult angelfish.

Geographic origin and habitat

Reference countries: Brazil, Colombia, Peru, Guyana, Suriname and French Guiana, broadly within the Amazon Basin. In the wild, Pterophyllum scalare inhabits calm or slow-moving areas of forested waterways, including margins, backwaters and sections filled with branches and vegetation. Water may be soft and acidic, often stained by organic matter, although conditions vary between drainage systems and seasons. In the aquarium, a temperature of 26 to 29 °C, slightly acidic to neutral pH and good stability are generally suitable. The layout should include tall plants, roots and visual barriers. This structure reduces chasing and allows fish to establish separate areas. Strong, turbulent flow is usually less appropriate than gentle circulation.

Specific location and local name

The trade name Amapa Red Back refers to Amapá, a state in northern Brazil, but here it functions as an aquarium-variety name rather than a precise scientific collection locality guaranteed for every fish sold under that label. In Brazil, the species is called acará-bandeira or peixe-bandeira; in English, angelfish is the usual common name. Across the Amazon Basin, it occupies sheltered habitats rather than fast current. Wooded margins, submerged roots and emergent or submerged plants provide important landmarks. In an aquarium, vertical plants and carefully placed wood reproduce its surroundings more effectively than a completely open layout with excessive circulation.

Appearance and physical characteristics

The body of Pterophyllum scalare is strongly compressed and has a triangular outline emphasized by the elongated dorsal and anal fins. The threadlike pelvic fins also help the fish sense its surroundings in cluttered habitats. The Amapa Red Back is mainly recognized by its reddish to copper-colored back, depending on the strain, age, lighting and condition. Color can become stronger in healthy adults kept against a darker background. Fish measured with their fins extended may be much taller than the body is long, so aquarium height matters. Sex is difficult to determine outside breeding condition. A ready female may have a fuller abdomen, while the shape of the genital papilla is the most useful indicator near spawning.

General diet

Pterophyllum scalare is an omnivore with a carnivorous tendency and readily accepts a varied diet. A base of quality cichlid pellets, sized for its mouth, can be supplemented with frozen foods such as brine shrimp, mysis or mosquito larvae. Live foods may encourage natural hunting behavior, but they should come from a reliable source to reduce health risks. Juveniles should receive small, frequent meals, while adults benefit from measured portions to prevent obesity. A varied diet helps maintain coloration and vitality without making rich foods the sole component of the menu. Any uneaten food should be removed promptly to protect water quality.

Essential data

• Name of native river: Amazon River basin
• Local name used: acará-bandeira; peixe-bandeira
• Origin of the scientific name: name assigned when the species was described
• Etymology of the full name: Pterophyllum means “leaf-shaped fin”; scalare means “ladder-like”
• Common/vernacular names: angelfish, freshwater angelfish, scalaire, Amapa Red Back
• Family: Cichlidae
• Subfamily: Cichlinae
• Name pronunciation: ter-oh-FIL-um skah-LAH-reh
• Discovery: Johann Jakob Heckel, 1840
• Maximum adult size: about 15 cm body length; approximately 25 to 30 cm tall including the fins
• Water temperature and pH: 26 to 29 °C; pH 6.0 to 7.5
• Waterway appearance and surrounding vegetation: calm water, forest margins, roots, submerged branches and dense vegetation
• Typical tank mates: Hemigrammus rhodostomus, Hoplisoma panda, Otocinclus affinis, Geophagus altifrons
• Temperament and behavior: generally peaceful, but territorial as a pair and predatory toward very small fish
• Water depth: sheltered areas of variable depth, often near banks and vegetation
• Sexual dimorphism: difficult to distinguish; the genital papilla is more informative during spawning
• Bottom configuration and flow: sandy or muddy bottom, plant debris and low to moderate flow

For aquarium success

Success with Pterophyllum scalare depends mainly on a tall, well-structured aquarium, stable water and carefully selected companions. Maintain good water quality, provide resting areas among plants and avoid aggressive tank mates or fish small enough to be swallowed. A group of juveniles can develop naturally until pairs form. Spawning then brings stronger territorial defense. Regular water changes, varied food and a consistent temperature help preserve the health and coloration of this popular aquarium strain.