How To Keep Altum Angelfish
How to Keep Altum Angelfish: A Guide to Caring for the King of Freshwater Angels
Altum Angelfish (Pterophyllum altum), often called the “true angelfish,” are prized for their tall bodies, graceful fins, and refined temperament. Native to the Orinoco and Amazon river systems, Altums are larger, more sensitive, and far more majestic than their commonly kept relatives (Pterophyllum scalare).
Caring for Altum Angelfish requires experience, patience, and the right setup—but when done right, it’s one of the most rewarding freshwater fishkeeping experiences.
Altum vs. Common Angelfish: What’s the Difference?
Body shape: Altums have a much taller body and more pronounced forehead dip (nuchal indentation)
Size: Can reach up to 15 inches tall and 7 inches long
Temperament: Peaceful but shy; require more space and calm tankmates
Water preferences: Much softer and more acidic than scalare angelfish
Hardiness: Wild-caught Altums are delicate and sensitive to change; tank-raised are more adaptable
Ideal Tank Setup for Altum Angelfish
Tank Size: Minimum 75 gallons, but 120+ gallons is ideal for a group
Tank Height: At least 24 inches tall to accommodate their vertical profile
Group Size: Keep in groups of 5–7 to reduce aggression and help them feel secure
Aquascape:
Use tall plants like Vallisneria, Amazon swords, and jungle-style driftwood
Add leaf litter or botanicals to mimic blackwater habitat
Dim lighting (or floating plants) reduces stress
Substrate: Sand or fine gravel; use botanicals to enhance tannins
Water Parameters
Altums require very clean, soft, acidic water with excellent stability.
Temperature: 82–86°F (28–30°C)
pH: 4.5–6.5
GH: 0–3 dGH
KH: 0–1 dKH
TDS: 30–100 ppm
Filtration: Use gentle but powerful filtration (canister + sponge) with blackwater additives
Always use RO/DI water and remineralize as needed. Weekly large water changes (30–50%) are essential.
Acclimation and Quarantine
Wild-caught Altums are sensitive to ammonia spikes, pH swings, and poor acclimation.
Drip acclimate slowly over several hours
Quarantine for 4–6 weeks to watch for parasites (common in wild imports)
Add tannins (from almond leaves or peat) to reduce stress
Tank-raised Altums are more forgiving but still benefit from soft, clean water.
Diet and Feeding
Altum Angelfish are omnivores and thrive on variety.
Staples:
High-quality flakes or soft sinking pellets
Frozen and live foods: bloodworms, brine shrimp, blackworms, daphnia
Occasional veggie-based foods (spirulina, algae wafers)
Feed 2–3 times daily in small amounts. Don’t overfeed—clean water is priority #1.
Tank Mates
Altums are peaceful but can be shy or outcompeted by aggressive fish. Ideal tank mates include:
Peaceful tetras (e.g., rummynose, cardinal, ember)
Corydoras catfish
Hatchetfish
Smaller, calm plecos (like L397 or L204)
Avoid:
Fin-nippers (barbs, some danios)
Aggressive cichlids
Common scalare angelfish (which can dominate)
Breeding Altum Angelfish (Advanced)
Altum breeding in captivity is rare and considered challenging.
Requires high, soft, warm water and a well-established pair
Pairs are hard to form and may take years to mature
Breeding may occur on vertical surfaces like slate or driftwood
Many breeders artificially hatch eggs to avoid fungus or predation
If you're serious, start with tank-raised juveniles and grow them out in optimal water over time.
Final Thoughts
Altum Angelfish are the crown jewel of the freshwater hobby—graceful, intelligent, and utterly unique. While they require more attention than standard community fish, the reward is a display of stunning beauty and natural behavior rarely matched in home aquariums. With soft water, patience, and care, your Altums will thrive and become the centerpiece of your aquatic world.
