Rio Nanay Altum Angelfish (Scalare Peru)

The Rio Nanay Angelfish (Pterophyllum scalare), often called “Peru Altum,” is a striking wild variant of the angelfish found in the slow-moving waters of the Rio Nanay, a tributary of the Amazon River in Peru. Known for its tall, elegant fins and intricate patterns, this angelfish is highly sought after by aquarists. While it resembles the true Altum Angelfish (Pterophyllum altum), it is a variant of Pterophyllum scalare and is easier to care for.

Tank Requirements

• Tank Size:
  • A minimum of 55 gallons for a small group (4–6).
  • Larger groups require tanks of 75 gallons or more to reduce territorial aggression.
• Tank Setup:
  • Vertical decorations like driftwood and tall plants mimic their natural environment and provide shelter.
  • Soft substrate such as sand or fine gravel.
  • Floating plants to diffuse light and create shaded areas.
• Lighting: Low to moderate; too much light can stress these fish.
• Water Flow: Gentle, mimicking their natural slow-moving waters.

Water Parameters

• Temperature: 78–84°F (25–29°C)
• pH: 5.5–7.0 (slightly acidic is ideal)
• Hardness: Soft to moderately soft water (2–10 dGH)
• Ammonia/Nitrite: 0 ppm; nitrates should be kept below 20 ppm.
• Water Changes: Weekly water changes of 20–30% are essential to maintain water quality.

Diet

These omnivorous fish thrive on a varied diet:

• Staple Foods:
  • High-quality flakes or pellets designed for angelfish or other omnivorous cichlids.
• Live/Frozen Foods:
  • Bloodworms, brine shrimp, daphnia, and blackworms.
• Vegetable Matter:
  • Offer blanched spinach, zucchini, or algae wafers occasionally.
• Feeding Schedule: Feed 2–3 times daily in small portions.

Behavior and Compatibility

• Temperament:
  • Generally peaceful but can be territorial, especially during breeding.
  • Works well in community tanks with appropriate tankmates.
• Tankmates:
  • Compatible with peaceful, similarly-sized species like tetras, Corydoras, peaceful dwarf cichlids, and small plecos.
  • Avoid fin-nippers (e.g., tiger barbs) and overly aggressive species.
• Social Structure:
  • Keep them in groups of 4–6 to reduce stress and spread out any aggression.

Breeding

Breeding Rio Nanay Angelfish is achievable in captivity:

1. Pair Formation: Allow a group to form pairs naturally as they mature.
2. Breeding Setup:
   • A separate breeding tank of 20–30 gallons with soft, acidic water (pH 5.5–6.5) and a temperature of 82–84°F.
   • Provide flat surfaces like leaves, slate, or vertical decorations for egg-laying.
3. Spawning Behavior:
   • The female lays eggs, and both parents guard and aerate the eggs.
   • Eggs hatch in 2–3 days, and fry become free-swimming within a week.
4. Fry Care:
   • Feed fry with infusoria, followed by baby brine shrimp as they grow.

Common Challenges

1. Water Sensitivity: They are sensitive to fluctuations in water quality and chemistry.
2. Aggression During Breeding: Pairs can become territorial and may need to be separated from other tankmates.
3. Wild-Caught Specimens: May take time to acclimate to prepared foods and aquarium conditions.
4. Health Issues: Prone to parasitic infections; quarantine new fish before introducing them to the tank.

Interesting Facts

• The Rio Nanay variant is distinguished by its unique markings, including pronounced vertical stripes and spots that enhance its beauty.
• Unlike true Altums, these angelfish are smaller and easier to keep in home aquariums.
• They use their tall, narrow body shape to navigate through submerged roots and vegetation in the wild.

Care Summary

Aspect	Details
Tank Size	Minimum 55 gallons for groups
Water Parameters	pH 5.5–7.0, 78–84°F, soft water
Diet	Omnivorous: flakes, pellets, live/frozen foods
Temperament	Peaceful with mild territorial tendencies
Lifespan	8–12 years

The Rio Nanay Altum Angelfish is a captivating choice for aquarists looking for a slightly exotic angelfish that combines beauty with relative ease of care. Proper tank setup, water quality, and a well-rounded diet will ensure these fish thrive and display their full potential.