''Pterophyllum'' is a small
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
of
freshwater
Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include ...
fish from the
family
Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...
Cichlidae
Cichlids are fish from the family Cichlidae in the order Cichliformes. Cichlids were traditionally classed in a suborder, the Labroidei, along with the wrasses ( Labridae), in the order Perciformes, but molecular studies have contradicted thi ...
known to most aquarists as angelfish. All ''Pterophyllum'' species originate from the
Amazon Basin
The Amazon basin is the part of South America drained by the Amazon River and its tributaries. The Amazon drainage basin covers an area of about , or about 35.5 percent of the South American continent. It is located in the countries of Bolivi ...
,
Orinoco Basin
The Orinoco Basin is the part of South America drained by the Orinoco river and its tributaries. The Orinoco watershed covers an area of about 990000 km2, making it the third largest in South America, covering most of Venezuela and eastern p ...
and various rivers in the
Guiana Shield
The Guiana Shield (french: Plateau des Guyanes, Bouclier guyanais; nl, Hoogland van Guyana, Guianaschild; pt, Planalto das Guianas, Escudo das Guianas; es, Escudo guayanés) is one of the three cratons of the South American Plate. It is a ...
in tropical South America. The three species of ''Pterophyllum'' are unusually shaped for
cichlid
Cichlids are fish from the family Cichlidae in the order Cichliformes. Cichlids were traditionally classed in a suborder, the Labroidei, along with the wrasses ( Labridae), in the order Perciformes, but molecular studies have contradicted this ...
s 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
Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the leopard's spotted coat, the ...
. Angelfish are ambush
predators
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...
and prey on small fish and
macroinvertebrates
Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate s ...
. All ''Pterophyllum'' species form
monogamous
Monogamy ( ) is a form of Dyad (sociology), dyadic Intimate relationship, relationship in which an individual has only one Significant other, partner during their lifetime. Alternately, only one partner at any one time (Monogamy#Serial monogamy, ...
pairs.
Eggs
Humans and human ancestors have scavenged and eaten animal eggs for millions of years. Humans in Southeast Asia had domesticated chickens and harvested their eggs for food by 1,500 BCE. The most widely consumed eggs are those of fowl, especial ...
are generally laid on a submerged log or a flattened leaf. As is the case for other cichlids, brood care is highly developed.
''Pterophyllum'' should not be confused with
marine angelfish
Marine angelfish are perciform fish of the family Pomacanthidae. They are found on shallow reefs in the tropical Atlantic, Indian, and mostly western Pacific Oceans. The family contains seven genera and about 86 species. They should not be conf ...
,
perciform fish found on shallow ocean
reef
A reef is a ridge or shoal of rock, coral or similar relatively stable material, lying beneath the surface of a natural body of water. Many reefs result from natural, abiotic processes— deposition of sand, wave erosion planing down rock out ...
s.
Species
The currently recognized species in this genus are:
History
The freshwater angelfish (''P. scalare'') was described in 1824 by F. Schultze. ''Pterophyllum'' is derived from the
Greek
Greek may refer to:
Greece
Anything of, from, or related to Greece, a country in Southern Europe:
*Greeks, an ethnic group.
*Greek language, a branch of the Indo-European language family.
**Proto-Greek language, the assumed last common ancestor ...
πτερον, ''pteron'' (fin/sail) and φυλλον, ''phyllon'' (leaf).
In 1906, J. Pellegrin described ''P. altum''. In 1963, ''P. leopoldi'' was described by J. P. Gosse.
Undescribed species
In taxonomy, an undescribed taxon is a taxon (for example, a species) that has been discovered, but not yet formally described and named. The various Nomenclature Codes specify the requirements for a new taxon to be validly described and named. U ...
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 (complete) 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
''Pterophyllum scalare'', most commonly referred to as angelfish or freshwater angelfish, is the most common species of ''Pterophyllum'' kept in captivity. It is native to the Amazon Basin in Peru, Colombia, and Brazil. Particularly to the Ucayali ...
''. Most of the individuals in the aquarium trade are captive-bred. Sometimes, captive-bred ''
Pterophyllum altum
''Pterophyllum altum'', also referred to as the altum angelfish, deep angelfish, or Orinoco angelfish, occurs strictly in the Orinoco River Basin and the Upper Rio Negro watershed in Southern Venezuela, Southeastern Colombia and extreme Norther ...
'' is available. ''
Pterophyllum leopoldi
''Pterophyllum leopoldi'', also referred to as the teardrop angelfish, Leopold's angelfish dwarf angelfish, or roman-nosed angelfish, is an angelfish species native to the Amazon River (between Manacapuru and Santarém), Essequibo River and Ru ...
'' is the hardest to find in the trade.
Care
Angelfish are kept in a warm aquarium, ideally around 80 °F (27 °C), with soft and acidic (<6.5ph) water. Though angelfish are members of the cichlid family, they are generally peaceful when not mating; however, the general rule "
big fish eat little fish" applies. Suitable tank mates include Raphael catfish which have their own armour for protection.
Breeding
![Angelfish breeding](https://upload.wikimedia.org/wikipedia/commons/8/85/Angelfish_breeding.jpg)
''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
In biology, detritus () is dead particulate organic material, as distinguished from dissolved organic material. Detritus typically includes the bodies or fragments of bodies of dead organisms, and fecal material. Detritus typically hosts commun ...
and
algae
Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...
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.
Aquarium varieties
Most strains of angelfish available in the fishkeeping hobby are the result of many decades of
selective breeding
Selective breeding (also called artificial selection) is the process by which humans use animal breeding and plant breeding to selectively develop particular phenotypic traits (characteristics) by choosing which typically animal or plant mal ...
. For the most part, the original crosses of wild angelfish were not recorded and confusion between the various species of ''Pterophyllum'', especially ''P. scalare'' and ''P. leopoldi'', is common. This makes the origins of "domestic angelfish" unclear. Domestic strains are most likely a collection of genes resulting from more than one species of wild angelfish, combined with the selection of
mutation
In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, mi ...
s in domesticated lines over the last 60 or more years. The result of this is a domestic angelfish that is a true hybrid, with little more than a superficial resemblance to wild ''Pterophyllum'' species.
Much of the research into the known genetics of ''P. scalare'' is the result of the research of Dr. Joanne Norton, who published a series of 18 articles i
''Freshwater and Marine Aquarium Magazine''
![Silverangelfish](https://upload.wikimedia.org/wikipedia/commons/0/0d/Silverangelfish.jpg)
*Silver (+/+): The silver angelfish most commonly resembles the wild form of angelfish, and is also referred to as "wild-type". It is not, however, caught in the wild and is considered domestic. The fish has a silver body with red eyes, and three vertical black stripes that can fade or darken depending on the mood of the fish.
*Gold (g/g): The genetic trait for the gold angelfish is recessive, and causes a light golden body with a darker yellow or orange color on the crown of the fish. It does not have the vertical black stripes or the red eye seen in the wild angelfish.
*Zebra (Z/+ or Z/Z): The zebra phenotype results in four to six vertical stripes on the fish that in other ways resembles a silver angelfish. It is a dominant mutation that exists at the same locus as the stripeless gene.
*Black lace (D/+) or zebra lace (D/+ - Z/+): A silver or zebra with one copy of the dark gene results in very attractive lacing in the fins, considered by some to the most attractive of all angelfish varieties.
*Smokey (Sm/+): A variety with a dark brownish grey back half and dark dorsal and anal fins
*Chocolate (Sm/Sm): Homozygous for smokey with more of the dark pattern, sometimes only the head is silver
*Halfblack (h/h): Silver with a black rear portion, halfblack can express along with some other color genes, but not all. The pattern may not develop or express if the fish are in stressful conditions.
*Sunset blushing (g/g S/S): The sunset blushing has two genes of gold and two genes of stripeless. The upper half of the fish exhibits orange on the best specimens. The body is mostly white in color, and the fins are clear. The amount of orange showing on the fish can vary. On some, the body is a pinkish or tangerine color. The term blushing comes from the clear gill plates found on juveniles, with pinkish gills underneath.
*Koi (Gm/Gm S/S) or (Gm/g S/S): The koi has a double or single gene of gold marble with a double gene of stripeless. Their expression of orange varies with stress levels. The black marbling varies from 5%-40% coverage.
*Leopard (Sm/Sm Z/Z) or (Sm/Sm Z/+): Leopards are very popular fish when young, having spots over most of their bodies. Most of these spots grow closer together as adults, so they look like chocolates with dots.
*Blue blushing (S/S): This wild-type angelfish has two stripeless genes. The body is actually grey with a bluish tint under the right light spectrum. An iridescent pigment develops as they age. This iridescence usually appears blue under most lighting.
*Silver gold marble (Gm/+): A silver angel with a single gold marble gene, this is a co-dominant expression.
*Ghost (S/+): Heterozygous for stripeless results in a mostly silver fish with just a stripe through the eye and tail. Sometimes, portions of the body stripes will express.
*Gold marble (Gm/g or Gm/Gm)
:Depending on whether the Gold Marble is single or double dose, the marbling will range from 5% to 40% coverage.
*Marble (M/+ or M/M or M/g or M/Gm): Marble expresses with much more black pattern than gold marble. The marbling varies from 50% to 95%.
*Black hybrid (D/g or D/Gm): A cross of black with a gold, the result is black hybrids, a very vigorous black that may look brassy when young. This cross does not breed true.
*Pearlscale (p/p): Pearlscale is a scale mutation, also called the "diamond" angelfish in some regions due to the gem-like iridescence on its scales. The scales have a wrinkled, wavy look that reflects light to create a sparkling effect. Pearl develops slowly, starting at around 9 weeks of age. In can be inhibited by stressful conditions. It is recessive, requiring both parents to contribute the allele.
*Black ghost (D/+ - S/+): Similar to a ghost, it has a darker appearance due to the dark gene, and very similar to a black lace without complete stripes. Ghosts generally have more iridescence than normal.
*Albino (a/a): Albino removes dark pigments in most varieties. Some, like albino marble still have a little black remaining on a percentage of the fish. The eye pupils are pink as in all albino animals. The surrounding iris can be red or yellow depending on the variety.
References
External links
{{Authority control
Heroini
Cichlid genera
Taxa named by Johann Jakob Heckel