Altum angelfish (Pterophyllum altum) are beautiful fish that live in freshwater Amazon River in South America. Altum are popular among experienced fish keepers because of their unique appearance and the challenge they present in care. They need a large tank with lots of space to swim and water should be slightly acidic and not too hard. In this article, we’ll discuss where altums are found, what sets them apart from common freshwater angelfish, as well as how to care for them, feed them, choose suitable tank mates, and breed them.
Contents
Habitat in the wild
Among the three known species of freshwater angelfishes, Pterophyllum altum stands out as the largest and arguably the most enigmatic. Found primarily in the vast river systems of South America, this remarkable fish has long captivated both scientists and aquarists alike. However, due to its wide distribution across the continent, identifying individual species in the wild has often proven challenging. Today, the Pterophyllum genus consists of three recognized species: Pterophyllum scalare, Pterophyllum altum, and Pterophyllum leopoldi.
The first formal description of Pterophyllum altum was made in 1903 by French ichthyologist Jacques Pellegrin (1873–1944), whose work significantly advanced the study of freshwater fish. The species name “Altum” comes from the Greek word for “tall” or “high,” referring to its distinctive, vertically elongated body—a striking feature that sets it apart from its relatives.
Natural Habitat and Geographic Range
While the exact boundaries of the altum angelfish’s habitat remain uncertain, these fish are primarily found in the eastern regions of the Orinoco River basin in southern Venezuela. They thrive in both small and large river tributaries, as well as in the floodplain lakes that form during seasonal river overflows. The northern limit of their range extends to the Rio Meta, a tributary of the Amazon, located 100 kilometers north of Puerto Ayacucho. Further south, specimens have been observed in the rivers Rio Inírida and Rio Atabapo, where the first of its kind was officially recorded.
It’s estimated that Pterophyllum altum inhabits a vast area of approximately 2,500 kilometers, stretching from the Orinoco River to the upper reaches of the Amazon. Beyond this, however, the full extent of their habitat remains a mystery.
Adaptations to Diverse Waters
This species has adapted to a variety of water conditions, commonly residing in blackwater, transparent, and even whitewater environments, though they are most frequently found in the former two. Interestingly, individuals caught in different locations display unique color variations.
For example, altums from the Orinoco River tend to have bluish hues near their back and head, with small red spots scattered across their bodies. In contrast, those from the Rio Inírida boast significantly more red markings, while fish from the Rio Atabapo exhibit even greater concentrations of red across their scales.
Life in the Jungle Waters
The typical habitat for Pterophyllum altum is a secluded lagoon or jungle stream, with a depth of no more than two meters during the dry season. These waters have a pH level ranging between 4.5 and 6.5, depending on the season and location. Temperatures fluctuate from 28°C to 31°C year-round, dipping to 21°C during the rainy season. The hardness of the water rarely exceeds 10 dGH, making these environments unique for freshwater species.
Water flow in their natural habitat varies from slow-moving to rapid currents, providing different levels of oxygenation. Altums are often found in well-oxygenated areas with faster flows, which offer a more stable environment. When the rainy season arrives, vast areas of the rainforest flood, causing water levels to rise by as much as 10 meters, dramatically expanding the available habitat.
Air temperatures during the flood season can soar to 38°C in the shade, while the water remains slightly cooler at the surface, around 32°C, decreasing by just a degree or two at greater depths. The biotope’s floor is typically sandy or clay-rich, providing a fertile ground for various aquatic plants.
Ecosystem and Behavior
The altum angelfish shares its home with a variety of other species, including Geophagus, Apistogramma, and Discus. However, it also faces threats from predators such as anacondas and small caimans. Despite these dangers, altums have developed complex survival strategies. They often form small groups of 5-20 individuals, preferring the shallow, plant-rich coastal waters.
In areas with clay-rich shores, the organic layer thickens during the rainy season, creating an ideal substrate for plant life like Echinodorus. In sandy-bottomed biotopes, fallen leaves create a thick layer, providing both shelter and food for a variety of species. Towering Vallisneria grows in sunlit patches, while the snags of fallen trees, covered in moss, create a labyrinthine underwater landscape that offers shelter from predators.
When rivers overflow, bushes along the shores become submerged, offering an additional layer of protection and a prime location for egg-laying. The spring floods, in fact, provide an abundant breeding ground, as the fish’s habitat dramatically expands. As the waters recede in the dry season, these habitats shrink, concentrating fish into smaller areas, often around rock formations or submerged trees.
The Seasonal Struggle for Survival
By the end of the dry season, the water levels reach their lowest point, leaving only isolated stone formations as shelter. During this period, altum angelfish and neighboring species like Discus are drawn to these refuges. Thanks to their flat, elongated bodies, altums are well adapted to navigating the intricate maze of stones and branches, allowing them to evade predators and thrive in even the most challenging conditions.
Description
With their laterally compressed bodies and tall, elongated dorsal fins, altum angelfish cut a striking figure among their relatives, giving them a unique and unmistakable presence. These impressive fish are the largest of the Pterophyllum species, and their sheer size, paired with their graceful movements, makes them stand out in any aquatic setting.
The dorsal and anal fins of the altum angelfish can reach an impressive span of 35-40 cm, creating a flowing, elegant silhouette. Both fins shimmer with a soft pearl-gray hue, adding to their ethereal beauty as they glide through the water. The long, filament-like rays of the abdominal fins further enhance their sleek and delicate appearance. Their body is disk-shaped and sharply flattened on both sides, with a slender snout that gives them an air of refinement.
The altum’s base coloring varies from greenish-gray to olive drab, accented by a silvery sheen that reflects light, giving them a nearly metallic glow. Their back carries a subtle brownish-olive tone, deepening their natural camouflage. Along their body, four distinct lateral stripes run vertically, shifting in color depending on the fish’s mood and surroundings—ranging from intense black to soft gray. The first stripe stretches across their eye, while the second begins at the short dorsal rays and runs down near the anal fin. The third stripe arches from the top of the dorsal fin to the end of the anal fin, and the fourth marks the base of the caudal fin.
| Characteristic | Description |
|---|---|
| Scientific Name | Pterophyllum altum |
| Common Names | Altum angelfish, Orinoco angelfish; altum angel; altum fish |
| Native Region | Amazon River basin in South America |
| Maximum Size | 15-40 cm (6-16 inches) |
| Body Shape | Tall and elongated, laterally compressed |
| Dorsal Fin | Tall and elongated, reaching up to half the body height |
| Coloration | Silver or gray body with vertical black stripes |
| Lifespan | Typically 5-10 years in captivity |
| Temperament | Generally peaceful, may become territorial during breeding |
| Tank Size | Minimum 75 gallons (284 liters) |
| Water Parameters | pH: 5.5-7.0, Temperature: 24-28°C (75-82°F) |
| Water Hardness | Relatively soft water with low to moderate hardness |
| Diet | Omnivorous, accepts high-quality flakes, pellets, and live/frozen foods such as brine shrimp, bloodworms, and small insects |
| Breeding Behavior | Open-water spawners, lay eggs on broad-leaved plants or surfaces |
| Difficulty Level | Challenging to care for, recommended for experienced aquarists |
| Popularity | Sought after by experienced hobbyists for their unique appearance and rarity |
Pterophyllum altum VS Pterophyllum scalare
You can easily distinguish an altum angelfish from other Pterophyllum species, not only by its strikingly tall body and long, flowing fins—traits unique to the altum — but also by its distinct facial features. Its sharply angled snout is more pronounced than in other species, giving it a unique, upward-pointing profile. Additionally, the reddish hue of its stripes, coupled with extra wide bands across its body, further sets the fish apart. Even its scales are smaller and more tightly packed than those of its Pterophyllum cousins.
Compared to the more commonly known angelfish, the altum is significantly larger, taller, and slimmer, with a particularly large frons. Its snout angles upward in a way that’s visually striking, and the differences are especially noticeable in younger fish. Juvenile altums stand out from their age mates due to their extraordinary long fins, which give them a majestic and graceful appearance in the water.
There are also more subtle features used in scientific classification. These include the specific number of fin rays, scale rows, and the presence of pores along the lateral line, all of which help to define the species more precisely.
Four dark vertical stripes, which sometimes appear almost black depending on the fish’s mood, are characteristic of the altum. When under stress, these stripes can increase in number, growing to as many as seven. The additional stripes are paler and form between the primary black ones, subtly changing the fish’s appearance. As fish age, their colors intensify. By the time they reach one year, greenish-blue hues emerge prominently across their forehead and back, while the spaces between are filled with reddish-brown accents.
Here’s a simple comparison table highlighting the differences between Pterophyllum altum and the Pterophyllum scalare:
| Altum Angelfish | Common Angelfish | |
|---|---|---|
| Scientific Name | Pterophyllum altum | Pterophyllum scalare |
| Origin | Amazon River basin in South America | Amazon River basin in South America |
| Size | Up to 15-40 cm (6-16 inches) | Up to 15 cm (6 inches) |
| Body Shape | Tall and elongated | Flatter and rounder |
| Dorsal Fin | Tall and elongated | Shorter and more rounded |
| Coloration | Silver or gray body with black vertical stripes | Varied color patterns, including silver, black, and marbled |
| Difficulty Level | More challenging to care for | Easier to care for |
| Tank Size | Requires a larger tank, minimum 150 gallons (568 liters) | Can be kept in smaller tanks, minimum 30 gallons (113 liters) |
| Water Conditions | Prefer soft and slightly acidic water (pH 5.5-7.0) | Tolerate a broader range of water conditions |
| Temperament | Generally peaceful but can be territorial during breeding | Generally peaceful, but aggression can occur during breeding |
| Breeding | Challenging to breed in captivity | More commonly bred in captivity |
| Availability | Less common and sought after by experienced hobbyists | More readily available in the aquarium trade |
Atabapo altum angelfish
These angelfish are renowned not only for their striking beauty but also for their unique characteristics that set them apart from other altum populations. Their rarity and majestic appearance make them a centerpiece in any freshwater collection.
Atabapo altums are distinguished by their exceptional size and elegant, elongated bodies. Towering at nearly 15 inches (38 cm) in height, they are one of the largest species of freshwater angelfish. Their sweeping dorsal and anal fins extend gracefully, giving them an even more regal presence in the water. Interestingly, unlike other variants, some Atabapo altums lack the pronounced vertical black bands on their bodies, with some individuals displaying these markings only faintly or not at all, adding to their unique charm.
When it comes to care, Atabapo altums have similar needs to their relatives, though their larger size demands special attention. These fish thrive in soft, slightly acidic water with temperatures between 78 and 84°F (25 to 29°C). A spacious aquarium is essential, with plenty of vertical swimming space to accommodate their impressive height and natural behavior. Providing hiding spots, such as driftwood and plants, mimics their natural habitat and helps them feel secure. Due to their size, these majestic angelfish need large aquariums to support their growth and ensure their well-being.
Difficulties in keeping
Altum angelfish are moderately challenging to keep in a home aquarium, primarily due to their sensitivity to water quality and environmental changes.They are highly sensitive to polluted water and require pristine conditions, making regular water maintenance crucial. Sharp movements or abrupt changes in lighting can startle them, causing stress. This sensitivity makes them best suited for peaceful community tanks with other non-aggressive species, though it’s important to avoid housing them with fin-nipping fish, as their long, flowing fins make them easy targets.
Altums can thrive in a community tank, but the tank should be tall with plenty of vertical swimming space to accommodate their height. Their elegant, fluid movements make them a stunning addition to large tanks, where they glide effortlessly through the water, bringing a touch of natural beauty to any aquarium setup.
While modern breeding techniques have made fish more accessible, wild-caught specimens still hold a special allure for collectors. The first altums introduced to hobbyist tanks were wild-caught, and they commanded high prices due to their rarity. Even today, despite advances in captive breeding, wild-caught altums remain sought after by enthusiasts, with some still appearing in the market.
Keeping in a tank
Lifespan
In a well-maintained aquarium, the lifespan of an altum angelfish typically ranges from 5 to 10 years. However, with optimal care and a carefully controlled environment, these graceful fish can sometimes exceed this, living up to 15 years or more in rare cases.
One of the most critical factors affecting their lifespan is water temperature. Warmer water accelerates their metabolic processes, which can shorten their overall lifespan. Keeping the temperature within recommended levels not only ensures their comfort but also promotes longevity. The higher the temperature, the faster their metabolism, which can reduce their lifespan. Therefore, it’s essential to strike the right balance to ensure a healthy, long life for your fish.
Aside from temperature, factors such as genetics, nutrition, and water quality also play key roles in their longevity. Regular water changes, high-quality food, and a stress-free environment all contribute to the well-being of these delicate fish. Every altum is unique, and their lifespan can vary based on the care and attention they receive.
Tank size
Altum angelfish require a generously sized tank to thrive. Ideally, a tank of at least 150 gallons (700 liters) is recommended to accommodate their size and swimming needs. While some hobbyists have successfully kept altums in smaller tanks, success in these cases often hinges on several factors, including the number of fish, the effectiveness of water filtration, and the nature of their tank mates. As a general rule, each adult fish needs a minimum of 11 gallons (50 liters) of water to maintain optimal health.
These fish are particularly sensitive to their environment, reacting to peripheral disturbances in ways similar to discus fish. Therefore, it’s crucial to place the tank in a location that minimizes noise and sudden movements. A noisy or crowded environment can stress the fish, while a quiet, secluded spot may not always be ideal either. Abrupt changes in lighting or loud noises can startle the altums, causing them to strike the tank walls and potentially injure themselves.
Wild-caught fish are typically more timid than their captive-bred counterparts. This heightened sensitivity can sometimes mask underlying health issues that may not be immediately apparent. It’s important to monitor their behavior closely and ensure their environment is as stable and stress-free as possible to prevent injuries and detect any potential health problems early.
Tank bottom substrate and decorations
When setting up a tank for altums, there are two main design approaches to consider: tanks with hygienic design and those with traditional substrate and decorations.
Hygienic design tanks, which are often used for keeping discus fish, may have no substrate at all. While these tanks are highly effective at maintaining cleanliness and preventing bacterial buildup, they lack decorative value and can appear quite sterile. The glass bottom of such tanks is relatively easy to keep clean, which helps avoid the accumulation of harmful bacteria.
In contrast, tanks with a substrate, decorations, and plants offer a more natural and visually appealing environment for altum angelfish. A practical compromise is to use a thin layer of clean sand on the bottom of the tank. This sand layer not only mimics some of the altum angelfish’s natural habitats but also provides an ideal surface for beneficial nitrifying bacteria. These bacteria help break down leftover food and prevent the growth of pathogenic agents, contributing to a healthier tank environment.
Maintaining a sand substrate involves periodic cleaning. You can siphon off some of the sand, rinse it, and then return it to the tank, ensuring that it remains effective in supporting beneficial bacteria. Additionally, the sand substrate makes it easier for altum angelfish to find and consume their food.
Plants in the tank
When setting up a tank for altum angelfish, you have considerable flexibility in choosing plants. Angelfishes are generally indifferent to plants and won’t damage them, but the type of substrate you use can impact how well plants establish themselves. With a thin layer of sand as the substrate, plants may struggle to root properly. To ensure they thrive, it’s best to use ceramic containers styled to look like natural stones. These containers not only enhance the tank’s appearance but also provide a stable environment for the plants.
For the best results, opt for plants with long and wide leaves, such as various types of Echinodorus. These plants are ideal because their large leaves create a visually appealing and functional environment for the fish.
Proper lighting is crucial for both the plants and the fish. Aim to create a balance of well-lit and shaded areas in the tank. A lighting schedule of 10-12 hours per day is recommended. An automatic lighting system that turns the lights on and off at the same time each day can help maintain consistency. If your lighting fixture has multiple lamps, it’s beneficial to turn them on gradually over the course of an hour to mimic natural light changes.
In their natural habitat, altum angelfish experience varying light and shade. Therefore, providing a mix of lighted and shaded areas in the tank is essential for their well-being. Shaded areas serve as safe refuges for the fish, reducing stress and making them feel secure.
To further enhance the tank’s environment, consider adding oak, beech, or maple leaves to the substrate. These leaves not only improve the tank’s appearance but also help prevent harmful bacteria from developing. Remember to replace the leaves every two weeks to maintain their effectiveness.
Tall-growing plants and large leaves create a safe environment for the fish and can also serve as spawning sites. Additionally, large, branched pieces of driftwood can provide further shelter and contribute to a more natural setup.
By choosing the right plants and maintaining a well-balanced environment, you can create a beautiful and healthy tank that supports both the visual appeal and the well-being of your altum angelfish.
Water parameters and temperature
Keeping altum angelfish healthy and thriving in an aquarium relies heavily on maintaining high water quality. In their natural habitat, these fish are accustomed to very soft water, but in a tank setting, a balance must be struck. Given the typically smaller size of home aquariums, it’s practical to maintain water with moderate hardness, as this makes it easier to stabilize key water parameters.
Water Temperature and Flow
For altum angelfish, the water temperature should be slightly lower than that for discus fish, ideally between 27-28°C. They require strong aeration and good water circulation, which distinguishes them from discus fish that prefer less water movement. A robust filtration system is essential, as these fish thrive in well-oxygenated water with a steady flow.
Water Hardness and pH
You can keep altum angelfish in water with medium hardness and a pH level that is neutral or slightly alkaline. However, the quality of the water is paramount. Effective filtration and regular water changes are crucial to maintaining a clean environment. Aim to perform a 20-25% water change weekly to keep the water quality high.
Filtration and Maintenance
To reduce the presence of harmful organisms, consider using a UV sterilizer. A reliable filtration system, combining mechanical and biological filters, is essential for maintaining water quality. Ensure that the filters are functioning properly, as even a brief downtime can significantly disrupt the balance of beneficial bacteria, leading to increased nitrite levels.
High-capacity filters generally perform well for extended periods if properly maintained. Avoid frequent cleaning of the filter media; biological filters should only be rinsed in tank water to preserve beneficial bacteria.
Keeping Nitrate Levels Safe
To manage nitrate levels, conduct regular water changes, replacing at least 25% of the tank water each week. Additionally, promptly remove any waste, such as leftover food, dead plant material, and other debris, to prevent water quality issues.
Tank mates
In a community tank, fishes that dwell in middle and bottom water layers can be tank mates. Corydoras catfish are bottom-dwelling fish that can coexist peacefully with angelfishes. They help keep the substrate clean by scavenging for leftover food and debris. Make sure to choose a species that prefers similar water parameters, such as Corydoras sterbai or Corydoras panda
For the middle water layer, active middle-sized fishes will do. Thus the following tank dwellers can be good tank mates: black neon tetra, neon tetra, bloodfin tetra, cockatoo cichlid, corydoras julii, emperor tetra, flame tetra, panda cory, pygmy cory, ram cichlid, rummy nose tetra. The schooling behavior of cardinals can provide a visually appealing display alongside with such big fish.
All tetra and corydoras kinds above-mentioned are schooling fishes, so you should keep them in a tank in groups of at least 10 species. All the species should be healthy and pass 4 weeks guaranteed. The same requirement is true for bottom-dwelling fishes.
You shouldn’t keep altum with such small fishes as oto catfish or bristlenose pleco juveniles. Although these algae-eaters are rather welcome in tanks, their small size sooner or later provokes fish to treat them as its prey. When catching the juvenile, altum often can’t swallow them since the latter bristles its sharp fins and gets stuck in the hunter’s mouth, often harming it a lot. Often such injuries lead to the fish death.
Feeding
In the wild, altum angelfish have a varied diet that includes insects, worms, crustaceans, and the juveniles of other fish. This diverse diet helps them get all the nutrients they need. In an aquarium setting, many fish enthusiasts prefer to feed altum angelfish live or frozen foods, such as worms and insects. However, while these options can be part of their diet, they don’t fully meet all the nutritional needs and can sometimes introduce potential risks to the tank.
Avoiding Inappropriate Foods
It is crucial not to feed altum angelfish meat from warm-blooded animals, such as cows. They lack the necessary enzymes to digest this type of meat, which can lead to health issues.
Optimal Feeding Practices
A balanced and effective solution is high-quality dry food. This food is specially formulated to meet the dietary needs of altum angelfish, providing essential vitamins and probiotics while keeping the tank water clean. Ensure that you avoid feeding any questionable-quality food, as it may negatively impact the fish’s health and the water quality.
To keep your fish healthy, offer portions of food that they can consume within a few minutes. It’s best not to feed them right before turning off the tank lights in the evening.
Avoid Overfeeding
All angelfishes are known for their hearty appetites. Overfeeding can lead to digestive issues, such as difficulty breathing or bloating. If this occurs, the fish may appear uncomfortable for a few hours but should return to normal once their digestive system recovers.
By following these feeding guidelines, you can ensure that your altum angelfish remain healthy and your aquarium environment stays in balance.
Gender differences: male vs female
You can define gender for certain only during its spawning period. Otherwise, all secondary characteristics don’t provide an ironclad guarantee of exact fish definition. Thus, adult male species are a bit larger than females, have a taller body and sharp forehead. Also, they have more contrast coloring. But all mentioned above is quite relative and strongly depends on the tank conditions.
Often one can define the altum gender by the size of its fins. For example, males have two or more elongated rays on the end of their anal fin, while females have just one such ray. Also, the fish’s gender can be determined by its behavior, but for this, you’ll need some experience of keeping altums in a tank.
Breeding
Spawning altum fish, like many other cichlids, follows seasonal cycles. For the best results, aim to have your fish spawn between April and June. During this period, pairs typically form, separate from the group, claim a specific territory, and guard it fiercely.
In spacious tanks, you can either move the breeding pairs to a separate tank or leave them where they are. The latter is often preferable, especially for wild fish, which tend to be more timid than other types.
If only one gender of fish is present in the tank, you might see false spawning behavior, where two fish of the same gender mimic a pair.
To encourage spawning, adjust the tank water parameters. The water should be soft and slightly acidic. Ideal conditions include an electrical conductivity of 100 to 150 µS/cm and a pH between 5.5 and 6.0.
Feed the fish a varied diet in moderate portions. Typically, a breeding pair will use a tank wall or a large plant leaf as a spawning substrate. You can also provide ceramic cones, tubes, or flat surfaces like plumbing pipes for them to use.
During spawning, the fish will become very territorial and aggressive. You’ll notice changes in their appearance: their colors will become more vibrant, and the black spot above their eye will become more pronounced. Female fish will develop a noticeable egg-laying organ, and males will have a distinct reproductive organ. This indicates that spawning is imminent, usually within two days. Minimize noise and sudden movements around the tank during this time.
The female will lay eggs in lines along the substrate, which the male fertilizes simultaneously. Spawning typically occurs around midday and can last up to 1.5 hours, with the female laying between 300 and 500 eggs.
The clutch is considered fertilized if you see protein spots on the eggs a few hours later. These spots indicate that embryos are developing. The eggs are almost transparent with a slight yellowish tint.
Post-spawning, the breeding pair will care for the eggs by fanning them with their fins and removing debris. Unfortunately, in tank conditions, the eggs often deteriorate and die within hours. This can be due to high water hardness or the presence of harmful bacteria. Even moving the eggs to a prepared tank with fewer bacteria may not always be effective if the eggs have been exposed to negative conditions for more than 90 minutes.
To maximize the number of viable juveniles, move the clutch to a separate tank immediately after spawning. Use an internal filter with peat to stabilize water acidity, but avoid using excessive peat. While antibacterial substances can help, UV sterilizers are generally more effective.
Larvae will hatch about 60 hours later and cling to the substrate or settle on the bottom. Once they consume their yolk sac, the juveniles will begin to swim in schools and search for food. Start feeding them with the smallest live food available.
The first three days are crucial for their development. Ensure they have ample water volume, frequent feeding, good filtration, and regular water changes.
Around 10-12 days old, the juveniles will start to change in appearance. They will grow taller, which will define their future body shape. As they approach 18 days old, lateral stripes will appear on their bodies. When their fin sweep reaches 4 cm, transfer them to a larger tank.
For successful growth, keep about 40-50 juveniles per 100 liters of water. You can then include a variety of foods they can eat within 10 minutes, feeding them 5-6 times a day.
Regularly remove food leftovers and waste, and perform partial water changes (50% of the tank volume, twice a week) to minimize harmful bacteria.
Altum fish generally grow more uniformly than other angelfish. Tank size is crucial for their growth. As they mature, gradually adjust their environment to use tap water with a pH of 7.5, a carbonate hardness of 4 dKH, and an electrical conductivity of 280 µS/cm. Maintain the tank water temperature around 28°C.
By one year of age, the fin sweep of altum fish can reach 20 cm. At two years, they can grow to 30 cm, and by three years, in spacious tanks, they can reach 35-40 cm.