Pterophyllum
Pterophyllum is a small genus of freshwater fish from the family Cichlidae known to most aquarists as angelfish. All Pterophyllum species originate in the Amazon Basin, Orinoco Basin and various rivers in the Guiana Shield in tropical South America. The three species of Pterophyllum are unusually shaped for cichlids, being greatly laterally compressed, with round bodies and elongated triangular dorsal and anal fins. This body shape allows them to hide among roots and plants, often on a vertical surface. Naturally occurring angelfish are frequently striped transversely, colouration which provides additional camouflage. Angelfish are ambush predators and prey on small fish and macroinvertebrates. All Pterophyllum species form monogamous pairs. Eggs are generally laid on a submerged log or a flattened leaf but can also be laid on filter piping when kept in an aquarium setting. As is the case for other cichlids, brood care is highly developed.
Pterophyllum should not be confused with marine angelfish, perciform fish found on shallow ocean reefs.
Species
The currently recognized species in this genus are:| Image | Scientific name | Distribution |
| Pterophyllum altum Pellegrin, 1903 | Orinoco River Basin and the Upper Rio Negro watershed in Southern Venezuela, Southeastern Colombia and extreme Northern Brazil | |
| Pterophyllum leopoldi | Amazon River, Essequibo River and Rupununi River. | |
| Pterophyllum scalare | Amazon Basin in Peru, Colombia, and Brazil |
History
The freshwater angelfish was described in 1824 by F. Schultze. Pterophyllum is derived from the Greek πτερον, pteron and φυλλον, phyllon.In 1906, J. Pellegrin described P. altum. In 1963, P. leopoldi was described by J. P. Gosse. Undescribed species may still exist in the Amazon Basin. New species of fish are discovered with increasing frequency, and, like P. scalare and P. leopoldi, the differences may be subtle. Scientific notations describe the P. leopoldi as having 29-35 scales in a lateral row and straight predorsal contour, whereas, P. scalare is described as having 35-45 scales in a lateral row and a notched predorsal contour. P. leopoldi shows the same coloration as P. scalare, but a faint stripe shows between the eye stripe and the first complete body stripe and a third incomplete body stripe exists between the two main body stripes that extends three-fourths the length of the body. P. scalare's body does not show the stripe between the eye stripe and first complete body stripe at all, and the third stripe between the two main body stripes rarely extends downward more than a half inch, if even present. P. leopoldi fry develop three to eight body stripes, with all but one to five fading away as they mature, whereas P. scalare only has two in true wild form throughout life.
Angelfish were bred in captivity for at least 30 years prior to P. leopoldi being described.
In the aquarium
Angelfish are one of the most commonly kept freshwater aquarium fish, as well as the most commonly kept cichlid. They are praised for their unique shape, color, and behavior. It was not until the late 1920s to early 1930s that the angelfish was bred in captivity in the United States.Species
The most commonly kept species in the aquarium is Pterophyllum scalare. Most of the individuals in the aquarium trade are captive-bred. Sometimes, captive-bred Pterophyllum altum is available. Pterophyllum leopoldi is the hardest to find in the trade.Care
Angelfish are kept in a warm aquarium, ideally around, with soft and acidic water. Though angelfish are members of the cichlid family, they are generally peaceful when not mating; however, they still may feed on very small species of fishes. Suitable tank mates include catfishes of the families Doradidae and Callichthyidae which have their own armor for protection.Breeding
P. scalare is relatively easy to breed in the aquarium, although one of the results of generations of inbreeding is that many breeds have almost completely lost their rearing instincts, resulting in the tendency of the parents to eat their young. In addition, it is very difficult to accurately identify the sex of any individual until it is nearly ready to breed.Angelfish pairs form long-term relationships where each individual will protect the other from threats and potential suitors. Upon the death or removal of one of the mated pair, breeders have experienced the total refusal of the remaining mate to pair up with any other angelfish and successfully breed with subsequent mates.
Depending upon aquarium conditions, P. scalare reaches sexual maturity at the age of six to 12 months or more. In situations where the eggs are removed from the aquarium immediately after spawning, the pair is capable of spawning every seven to 10 days. Around the age of three years, spawning frequency decreases and eventually ceases.
When the pair is ready to spawn, they choose an appropriate medium upon which to lay the eggs, and spend one or two days picking off detritus and algae from the surface.
This medium may be a broad-leaf plant in the aquarium, a flat surface such as a piece of slate placed vertically in the aquarium, a length of pipe, or even the glass sides of the aquarium. The female deposits a line of eggs on the spawning substrate, followed by the male, which fertilizes the eggs. This process is repeated until a total of 100 to more than 1,200 eggs are laid, depending on the size and health of the female fish. As both parents care for the offspring throughout development, the pair takes turns maintaining a high rate of water circulation around the eggs by swimming very close to the eggs and fanning them with their pectoral fins. In a few days, the eggs hatch and the fry remain attached to the spawning substrate. During this period, the fry survive by consuming the remnants of their yolk sacs. At one week, the fry detach and become free-swimming. Successful parents keep close watch on the eggs until then. At the free-swimming stage, the fry can be fed suitably sized live food.
P. altum is notably difficult to breed in an aquarium environment.
Lifespan
Freshwater Angelfish with quality genetics are known to live approximately 12 years in captivity, if the ideal living conditions are provided. In the wild they are thought to live as long as 15 years if unthreatened by their numerous natural predators.Compatibility with other fish
In pet stores, the freshwater angelfish is typically placed in the semiaggressive category. Some tetras and barbs are compatible with angelfish, but ones small enough to fit in the mouth of the angelfish may be eaten. Generous portions of food should be available so the angelfish do not get hungry and turn on their tank mates.P. scalare and P. altum are described to be peaceful but territorial. While freshwater angelfish are often recommended for community aquaria, it has been reported that fin-nippers, such as tiger barbs, often target their long fins, and that freshwater angelfish become aggressive towards their companions as they grow. It is thus recommended that freshwater angelfish be kept instead in single-species aquaria.