The Altum Angelfish is a majestic Orinoco cichlid with an incredibly tall body profile, demanding soft acidic water and dedicated aquarist care.
Overview
Pterophyllum altum is a true gem among freshwater cichlids and one of the most striking fish available for the home aquarium. Unlike the widely kept common angelfish, the altum is endemic to the Orinoco River basin and the upper Rio Negro in South America. It is often called the "true" angelfish and is regarded as the king among angels.
The defining feature of Pterophyllum altum is its remarkably tall body profile. Adult specimens with fully extended fins can reach 35 cm or more in height, significantly exceeding the dimensions of the common angelfish. Body length ranges from 20 to 25 cm. The coloration is silvery with dark vertical bars, and the characteristic notch on the forehead (the so-called "saddle-shaped" profile) makes it easy to distinguish the altum from other species in the genus Pterophyllum.
In the wild, these fish inhabit soft, acidic waters among submerged trees and roots, favoring calm stretches with subdued lighting. With proper care, their lifespan in an aquarium is 10-15 years.
Tank Requirements
Keeping Pterophyllum altum demands a serious approach to aquarium setup. The minimum volume is 200 liters, but for a group of 4-6 individuals, a tank of 300 liters or more is recommended. The key requirement is tank height: it should be at least 50-60 cm so the fish can fully extend their magnificent fins.
Water parameters are critically important for altum health. Temperature must be maintained at 26-30°C, pH at 5.5-7.0, and general hardness (GH) at 2-10. These fish are considerably more sensitive to water quality than common angelfish and do not tolerate hard or alkaline water well.
Use driftwood as decoration — it will naturally acidify the water and provide shelter. Tall plants such as Vallisneria and Echinodorus will help the fish feel secure. Choose dark, fine substrate — sand or fine gravel. Lighting should be subdued, mimicking the shaded stretches of tropical rivers.
Feeding and Diet
Pterophyllum altum is an omnivorous species with a strong preference for live foods. In the wild, their diet consists of small invertebrates, insect larvae, and aquatic organisms.
In the aquarium, the foundation of their diet should be high-quality live and frozen foods: bloodworms, brine shrimp, daphnia, and glassworms. Keep in mind that wild-caught specimens (and the vast majority of altums on the market are wild-caught) may initially refuse dry foods. Introduce pellets and flakes gradually by mixing them with familiar foods.
Feed adults twice daily in small portions that are consumed within 3-5 minutes. A varied diet is essential for vibrant coloration and strong immunity. It is also beneficial to skip feeding one day per week.
Care and Maintenance
Keeping altums requires discipline and attention to detail. Weekly water changes of 25-30% are mandatory — these fish do not tolerate the accumulation of nitrates and organic waste. Use water prepared with reverse osmosis or peat filtration to maintain the necessary softness.
It is important to remember that most Pterophyllum altum available for sale are wild-caught rather than captive-bred. This means heightened sensitivity to stress, fluctuations in water parameters, and disease. A quarantine period of 2-3 weeks after purchase is essential.
Regularly test water parameters. Pay particular attention to temperature — drops below 26°C can trigger illness. Altums are susceptible to ich and bacterial infections, especially under stress or in unsuitable conditions.
Ensure high-quality filtration with moderate flow. An external canister filter is the optimal choice for a tank housing these fish.
Compatibility
Pterophyllum altum is a fairly peaceful fish that coexists well with similarly sized, calm tank mates. Ideal companions include large tetras (such as Congo tetras and lemon tetras), peaceful corydoras and loricariid catfish, as well as certain dwarf cichlids.
Do not house altums with small fish that may be seen as prey, or with aggressive or overly active species. Fin-nipping barbs can damage the angelfish's long fins. It is also inadvisable to keep them together with common angelfish to avoid interspecific hybridization.
Altums feel most comfortable in a group of 4-6 individuals — this reduces stress and allows you to observe their natural social behavior. During spawning, pairs become territorial, so the aquarium must provide sufficient space.
Breeding
Breeding Pterophyllum altum in captivity is a challenge suited only for experienced aquarists. This species very rarely reproduces under aquarium conditions, and the vast majority of fish in the trade are wild-caught.
To stimulate spawning, ideal conditions must be created: very soft water (GH 2-4), pH 5.5-6.0, and a temperature of 28-30°C. The breeding tank should be tall, with vertical surfaces for egg deposition — broad-leaved plants, clay cones, or vertically positioned slates.
Pairs form naturally within a group, and this process cannot be forced. The female deposits eggs on a vertical surface, and both parents guard the clutch. Eggs incubate for 2-3 days at 28-30°C. After hatching, the larvae remain on the substrate for another 4-5 days, feeding on their yolk sacs. The first food for fry is freshly hatched brine shrimp nauplii.
The main difficulty in breeding lies in obtaining a healthy, well-adapted pair and maintaining stable water parameters throughout the entire process.