Altum Angelfish (Pterophyllum Altum)

Altum angelfish are the largest species of freshwater angelfish. They have three distinct vertical black and brownish stripes that easily distinguishes them from Pterophyllum Scalare. Additionally, true altums that haven’t been crossbred with Pterophyllum Scalare have an incision on the ridge of their nose, just below the eyes.

Origin & Habitat

Altum Angelfish are a freshwater species endemic to Venezuela, Colombia, and Brazil in South America. They can be found in the floodplains of the Atabapo and Inirida rivers as well as the upper Rio Negro, an Amazon River tributary, and tributaries of the upper Rio Orinoco including the Rio Inirida and Rio Atabapo.

Their native environment consists of highly acidic, soft blackwaters with slow currents and sandy substrates that are covered with debris from fallen trees, branches, and leaves. The waters in which they reside often overflow due to significant seasonal rainfalls, allowing these fish access to vast territories to spawn in.

Altum Angelfish Care

Altum angelfish are prone to disease and extremely sensitive to poor water quality; once they exhibit symptoms, they are very difficult to treat and typically succumb to sickness relatively quickly. The best approach to care for altums is to maintain a healthy environment from the very beginning, which may be done by performing weekly water changes of at least 50% and adhering to rigorous tank maintenance standards.

Since a good portion of all altums within the aquarium hobby are wild-caught, extra care will need to be taken when integrating them into an aquarium. In fact, seeking out tank-bred altums over wild-caught ones would be a sensible decision because the latter are subjected to a prolonged transit process that causes too much stress and typically leaves them in poor condition.

When first introduced to an aquarium, wild-caught altum angelfish may also act strangely; under stress, they may dart around and accidentally cause self-inflicted injuries by swimming directly into objects or the tank’s walls, which is ultimately fatal in most cases.

A relaxing atmosphere can be created by providing a sizable aquarium that is dimly lit, with floating plants and broad-leafed plants to further reduce the brightness, and has a black background attached to the back and sides. Before adding wild-caught altums, large pieces of driftwood should also be removed to prevent unintentional injuries. Once the altums have adapted to their new surroundings, the driftwood should be reinserted to mimic their natural habitat.

With a maximum length and height of around 12 inches, altum angelfish requires a lot of room to move around. Due to their lengthy dorsal, ventral, and anal fins, an appropriate-sized tank will be both long and deep that contain soft substrates.

As they do not thrive in hard, alkaline waters, aquariums should also contain soft water with minimal mineral content; it may be necessary to dilute demineralized or R/O water with your tap water.

They also prefer slow-moving waters, and even mild concentrations of nitrites and ammonia are intolerable. As a result, filtration units should be able to provide a massive surface area for beneficial bacteria to thrive without producing a strong current.

Altum Angelfish Diet & Feeding

Altum angelfish are omnivorous ambush predators that consume small fish, invertebrates, insects, larvae, plant matter, and algae in their natural habitat.

Both wild-caught and tank-bred altums must have a balanced diet that includes ingredients with high-quality protein and algae-based food. Wild-caught altums are likely to reject commercially prepared food, so you’ll probably need to start by feeding them live food before gradually weaning them onto prepared food.

The best foods for altum angelfish will include live, frozen, or dried sources, including brine shrimp, mosquito larvae, daphnia, mysis shrimp, and bloodworms. This should comprise the majority of their diet, although spirulina-fortified pellet and flake foods should also be frequently provided.

On occasion, some other excellent substitutes for the above-mentioned live, frozen, or dry food include commercially produced flake and pellets made specifically for discus or cichlids. Ingredients should mostly consist of spirulina, insect larvae, or brine shrimp that contain little to no ash and other fillers.

The key to a long and healthy life is a nutritious diet; the goal is to provide them with a varied and nutritionally balanced diet. Schedule a minimum of two to three feedings per day, and make sure to clean out any excess waste and excrement two or three times per week.

Tank Mates & Temperament

Altum angelfish are typically peaceful schooling fish, but during spawning seasons, males will attempt to establish territories, act aggressively, and engage in disputes with other males to protect their territory when paired with a female.

It is recommended to pair them evenly because a high male-to-female ratio will only encourage aggressiveness as the males compete with one another. More territories will be created in aquariums with lots of decorations; disrupting or dividing those territories can help lessen aggression, the objective is to create a line of sight throughout the aquarium.

Fast-swimming fish such as tiger barbs, which can easily outcompete the angelfish for food and species of fish less than 3″ in length, are not the best tank mates for the altum angelfish. Larger and more peaceful species of corydoras, discus, dwarf cichlids, gobies, gouramis, livebearers, sleepers, south American cichlids, tetras, loaches, and plecos would be ideal tank mates.

They will also readily consume smaller fish that they are capable of fitting in their mouth, as a consequence, small fish such as neon tetras, guppies, harlequin rasboras, or any other fish of comparable size should be avoided.

Male & Female Differences

Sexing younger male and female altum angelfish is extremely difficult; sexual dimorphic characteristics can only be observed in fully matured individuals.

A male will typically develop a larger and more protrusive crown called nuchal humps (humps or horns on their foreheads) commonly seen in most Cichlidae. Additionally, males have a short, pointed tube-like appendage on their underbellies in between their ventral and anal fins, whereas females have a blunt, triangular-shaped appendage.

Breeding & Spawning

Due to their demanding nature, true wild-caught altum angelfish are particularly challenging to reproduce in captivity. The majority are frequently found in well-oxygenated and exceptionally soft waters, where heavy seasonal rains help induce spawning by raising water levels upwards of 7.5 to 10 meters, which allows access to vast territories for them to explore.

To the greatest extent possible, mimicking their natural environment is the most effective method to promote spawning behavior. You’ll require at least two aquariums, one of which should be at least 200 gallons in capacity.

Only soft, acidic waters with a pH between 4.5 and 5.0, less than 25 ppm (1.4 dH) total dissolved minerals, and temperatures between 82.5°F (28°C) and 84°F (29°C) will support spawning. These water parameters can only be attained with either rainwater or demineralized water.

Tannin-stained waters will also need to be achieved to further reduce the pH to an appropriate level, by adding peat moss, driftwood, almond leaves, or coconut-derived materials. Altum angelfish also prefer to spawn in areas with gentle water circulation on submerged tree roots, broad-leafed plants, branches, and the sides of the tank.

Water quality will be paramount, with weekly water changes of 50% with one or two small 10% water changes throughout the week. So that any residual waste and excrement are cleaned out during tank maintenance, the aquarium’s base should only have a very thin layer of sand, less than 1 cm.

Once you’ve established all of the above water parameters, create a few separate territories before integrating two pairs of altum angelfish. Adding a pair of discus fish will likely improve your outcome with the altum angelfish throughout this initial spawning period. In a sense, they’ll show the angelfish how to effectively spawn, and once the discus lays eggs they can be removed.

It may take several weeks before altum angelfish form territories and successfully pair, when the male and female display extremely red dorsal and anal fins, spawning should occur shortly after. During this time, condition them on live foods such as mosquito larvae, mysis shrimp, and brine shrimp while adhering to strict tank maintenance standards.

You might begin to notice the female scouting several potential spawning grounds inside the aquarium by fanning and cleaning suitable areas. Once a spawning ground has been established, the female altum is capable of laying upwards of 600 eggs each clutch within a few hours.

All fish except for the male and female pair should be removed from the tank. However, do not split up the pair because both the male and female actively participate in rearing the larvae by alternately fanning the eggs day and night.

Start daily 10% water changes as soon as any eggs are noticeably present, to further oxygenate the water and avoid the growth of fungus, which will increase hatch rates. You should also siphon the substrate’s surface to collect any remaining waste.

Expired eggs that have turned white are constantly removed by the adults, using their mouths. 60 to 80 hours after fertilization, the first signs of movement in the larvae appear, and shortly after that the eggs hatch. The adults will continuously collect and transport the new fry to a secure nesting area with their mouths, and the parents will diligently protect and rear their young, by shuddering their fins to call their young when alarmed.

After hatching, the fry will spend the first week eating only from their yolk sac before swimming freely six to seven days later. Once their yolk sac has been depleted, the newly hatched fry will require four feedings per day with cultured infusoria and freshly hatched artemia for the first few weeks. They can start eating daphnia, baby brine shrimp, and other insect larvae after three or four weeks.

On day 30, the adults and young can be acclimated to tapwater standards by performing 10% water changes every day for the following seven days. However, the water’s parameters should always maintain low mineral content and an acidic state.

During the first 30 days of rearing the freshly hatched altum angelfish, it is highly recommended to continue the daily 10% water changes in order to remove any additional waste to reduce mortality rates.

More Information

Since the water level in their native river system is only low enough to permit effective fishing, true altum angelfish are often only available in aquarium stores from late summer to early fall.

In 1903, French zoologist Jacques Pellegrin published the first description of the altum angelfish. He also discovered roughly 350 new species of fish and penned over 600 scientific publications and papers.