The Altum Angelfish Pterophyllum altum is the largest of the three described angelfish species. They measure about 7 inches (18 cm) in length but are very tall, with extensive fins reaching up to around 9" (20 cm) in height. Although larger than its close and well known relative, the common Silver Angelfish Pterophyllum scalare, this disk shaped cichlid is very elegant and graceful. It is also known as the Orinoco Angelfish, Atlum Angel, and Deep Angelfish.
P. altum is distinguished from the other angelfish species by having a "notch" on the upper part of its snout rather than a more flat or slightly rounded forehead as on the other two species. In color and pattern it is very similar with a silver colored body and dark bars that are brownish/red. The fins can show red striations and adults may have some red spots and a blue-green cast to the dorsal fin. When aroused they will exhibit a black spot on the gill cover. Overall color differences can often be subtle, but all true P. altum will have the notch above the nares.
In the past it was only possible to obtain wild caught specimens of this fish. This was due to a high mortality rate which for years made the fish practically impossible to breed. More recently however, it has been successfully bred by some hobbyists and captive bred specimens are now occasionally available as well as wild caught. There are also hybrids being developed by cross breeding the P. altum with P. scalare and called the "Orinoco Altum". These hybrids may or may not show the notched trait of the true species, or may have it to a lesser degree.
The Altum is considered the most peaceful of all angelfish species. It is a bit timid however, and can be frightened by shadows and fast movements. This is especially true when first acquired, but once acclimated it is a friendly and personable fish. This angelfish is considered a community fish, but as a cichlid may not be as sociable with smaller fish. They will school peacefully when they are young, but tend to pair off and become more territorial when they are older.
They are moderately difficult to keep as they have more stringent requirements than the common angelfish. They need enough room to accommodate their size and swim freely. A 55 gallon tank would be the suggested minimum, but if you are keeping a pair or keeping them in a community, the tank will need to be larger. They will feel most at home and comfortable in a warmer aquarium that has roots and some rocks to offer places of refuge. They also like hardy plants placed around the inside perimeter, keeping an open area in the center for swimming.
The Altum Angelfish Pterophyllum altum was described by Pellegrin in 1903. They are found in rivers in South America; the Amazon River basin in the upper Negro River drainage and the Orinoco River basin in tributaries of the upper Orinoco River (Inírida and Atabapo rivers) to Puerto Ayacucho. Other common names they are known by are Orinoco Angelfish, Altum Angel, and Deep Angelfish.
In the wild these cichlids live in river watersheds and flood plains where there are moderate amounts of water flow, submerged tree and plant roots, and underwater vegetation. They are more frequently found in very soft and well oxygenated waters. As omnivores they feed on smaller fish and invertebrates as well as eating food particles in the water.
The Angelfish species are an attractive and graceful group of fish. Besides the Altum Angelfish, there are two other recognized species in the Pterophyllum genera. There are also thought to be several undescribed species. The other two described species are:
- Silver Angelfish Pterophyllum scalare
The common Angelfish sold today is generally considered to be a hybrid of Pterophyllum scalare, however, this may not be the case. Forms of Angelfish found in the wild have become fixed forms by captive inbreeding. The common Angelfish has historically been referred to as Pterophyllum scalare because this angelfish proved to be the hardiest and easiest to breed in captivity.
- Leopold's Angel Pterophyllum leopoldi
The Leopold's Angel must be imported to America and is fairly rare. Visually it appears very similar to the common Angelfish, but displays slightly different black bar patterning. It has a few vertical dark body bars, but is distinguished by a black blotch at the base of the dorsal final that doesn't extend into a full bar.
The Altum Angelfish is very similar to the wild form of the other angelfish species. But It is larger both in length and in height. It generally reaches about 7 inches (18 cm) in length and is about 9 inches (20 cm) in height from the tip of the dorsal fin to the tip of the anal fin. There are some reported anomalies of wild specimens reaching up to 19.6 inches (50 cm) in height and some aquarium specimens said to reach over 15.75 inches (40 cm) in height.
The body is laterally compressed with a distinctive diamond shape and steep forehead with a a "notch" on the upper part of its snout, just above the nares, and a steeply rising forehead. They have oversized extended dorsal and anal fins which, along with the tail fin, tend to be very long and flowing. In mature fish the tail fin can develop streamers on the outside corners. The Pelvic (ventral) fins are also very long and delicate. They can have a lifespan of 10 -15 years when properly cared for in a well maintained aquarium.
The body presents a general silver coloration which may be accented with a greenish tint. Three broad dark brownish/redish bars run vertically along the body in addition to some less prounounced and fainter bars. The fins can show red striations and adults may have some red spots and a blue-green cast to the dorsal fin. When aroused they will exhibit a black spot on the gill cover.
There are also hybrids being developed by cross breeding the P. altum with P. scalare and called the "Orinoco Altum". These hybrids may or may not show the notched trait of the true species, or may have it to a lesser degree.
Since they are omnivorous, the Altum Angelfish will generally eat all kinds of live, fresh, and flake foods. To keep a good balance give them a high quality flake food or pellet everyday. Feed brine shrimp (either live or frozen) or blood worms as a treat. You can even feed them lettuce or spinach. Feed mosquito larvae very sparingly as they will tend to over eat it. Overeating can result in a buildup of fats, which results in inactivity and could kill them.
A minimum 55 gallon aquarium is okay for a single fish, though a larger tank would be suggested if keeping more or keeping them in a community. They need good water movement along with very strong and efficient filtration. As they come from a natural environment with soft, well oxygenated water it is recommended to provide peat-filtered water.
Provide a warmer aquarium that has roots and some rocks to offer places of refuge. They also like hardy plants placed around the inside perimeter, keeping an open area in the center for swimming. They prefer subdued lighting. These fish do not burrow and will not damage plants as much as other cichlids.
The Altum Angelfish is more sensitive to its water conditions than the common angelfish, so is suggested for an aquarist with some fish keeping experience. It can be rewarding to keep for aquarists who are observant and diligent in providing care.
Though they are considered a community fish, Altum Angelfish may become territorial as they grow older. They are reportedly a more peaceful fish than other angelfish species, but being in the cichlid family smaller fish may not do well with them. As they mature they will pair off, developing a strong nuclear family, and defend a territory in which to breed. A nice thing about the Altum Angelfish is that they don't burrow or disturb plants!
The Altum Angelfish is a difficult fish to breed. For years it was considered impossible to breed. More recently it has been successfully bred by some hobbyists and captive bred specimens are now occasionally available. There are also hybrids being developed by cross breeding the P. altum with P. scalare called the "Orinoco Altum". The characteristic "notched" nose of the pure blooded fish may or may not present in the hybrid version, or it may simply appear less pronounced.
These fish are egg layers and form nuclear families. These egg layers are open breeders that prefer to spawn on submerged roots and tree branches in the wild. They are difficult to sex, so it's best to start with a small school of about 4 - 8 fish and let them establish pairs.
The pair will need very clean water and need to be conditioned to spawn. Supplement their current diet with foods rich in protein, but still be sure to not overfeed them. The breeding water should be soft, acidic, and warm. Have a pH between 5.8 - 6.2. hardness at 1 - 5° dGH, and temperatures between 86 - 87.8° F (30 - 31 ° C). The males sometimes make a loud grating sound with their jaws when mating.
The female will lay between a few hundred to over 1000 eggs on carefully cleaned leaves and the male will follow and fertilize them. If the parents don't eat the eggs, the larvae and fry are carefully guarded. The eggs will hatch in a few days and the fry will be free swimming in a week. The parents will swimming with a shoal of fry in tow. The fry can be fed newly hatched brine shrimp for the first week or two.