Pterophyllum
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| iFreshwater angelfish | ||||||||||||
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| Pterophyllum altum (Pellegrin, 1903) |
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| Pterophyllum leopoldi (Gosse, 1963) |
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| Pterophyllum scalare (Lichtenstein, 1823) |
Pterophyllum is a small genus of freshwater fishes from the family Cichlidae known to most aquarists as angelfish. All Pterophyllum species originate from the Amazon River basin in tropical South America. The three species of Pterophyllum are unusually shaped for cichlids being greatly laterally compressed, with round bodies and elongated triangular-shaped 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 longitudinally, 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 flattened leaf or submerged log. As is the case for other cichlids, brood care is highly developed.
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[edit] P. scalare
The best known species of angelfish is Pterophyllum scalare. Its natural color is silvery with three brownish vertical stripes. It is very peaceful (although sometimes can be aggressive to smaller fish, especially of its own breed) and is a popular aquarium fish. P. scalare, like all angelfish, comes from slow moving sections of rivers in the Amazon basin. Angelfish also do not inhabit dense vegetation except when very young, when they school together and hide in vegetation for protection. Adults are much more frequently found amongst sunken driftwood where very few plants grow. They spawn on broad-leaved sword plants in the wild, and prefer broad-leaved plants to spawn in an aquarium, if available. Its maximum size is around 12–15 cm (up to 6 inches) length, up to 20 cm (8 in.) height- although exceptional husbandry on the part of the owner can produce an angel up to nine inches in rare instances. These angelfish prefer water with a 6.0–8.0 pH,with 6.5-7.4 being ideal. a water hardness of 5.0–13.0 dGH, and a temperature range of 24–30°C (75–86°F).
Average lifespan in an aquarium is 10 years, but there have been reported instances of individuals living twice as long. Freshwater angelfish are piscivores, meaning that they eat other fish. In the wild angels sit just below the surface, waiting to lunge at unaware small fish that pass above them in the twilight of the early morning and late evening. However, in an aquarium, their predilection for laziness sets in and they rapidly show preference for slow moving processed food rather than having to run down larger, harder to chew live fish. They are safe to keep with other peaceful fish that are not too small (i.e. those that could fit in its mouth). For example, an angel that has never seen a neon tetra might eat a small one just out of instinct if it can fit in its mouth.
[edit] P. altum
The Pterophyllum altum, or Altum angel angelfish species originates from rivers in the Amazon River basin where the upper Negro River drains, and from the Orinoco River basin. Its natural color is also silvery with three brownish vertical stripes. Some of the largest angelfish are of this species, growing up to 18 cm (7 in) long and 25cm (10 in) These angelfish prefer water with a 4.8–6.2 pH, a water hardness of 1.0–5.0 dGH, and a temperature range of 27–31°C (81–88°F). Unlike P. scalare (mentioned above) which prefer to spawn on broad leaved plants, P. altum prefers to spawn on driftwood. Altum angels are true blackwater fish. Neon tetra and cardinal tetra come from similar water.
[edit] P. leopoldi
Formerly known as "Pterophyllum dumerilli". The Pterophyllum leopoldi is a river dwelling angelfish species that originates from rivers in the Amazon River basin along the Solimões River, Amazon River, and Rupununi River. Rarely available in the hobby, this fish can be discerned from Pterophyllum scalare in that P. leopoldi has a more horizontally elongated body than does P. scalare, and the black band which goes through the fish's eye does not sweep backwards towards the dorsal fin (as seen in P.scalare), but rather goes straight over the head and joins up on the other side.
[edit] Angelfish in the fishkeeping hobby
Most strains of angelfish available in the fishkeeping hobby are the result of many decades of selective breeding. 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 mutations 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. It would be inaccurate to say that they accurately represent any species of wild angelfish, although they most resemble P. scalare and are frequently referred to as such.
Domestic angelfish have been bred and crossbred for several decades. There are hundreds of mutations of little importance by themselves. 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 in Freshwater and Marine Aquarium (FAMA) Magazine. Those articles are reprinted at http://theangelfishsociety.org/genetics.htm .
[edit] Genetics of domestic angelfish
The following genes have had a major effect on the appearance of angelfish and whose inheritance characteristics have been discovered. The letter in parenthesis is the gene notation (shorthand used to track the genotype). These are the only mutations whose allelic inheritance are proven with documented research. Other genes are claimed to exist, but have not been scientifically proven to the public.
Albino (a)
- A recessive mutation that removes the pterin and melanin pigments leaving the carotenoid pigment layer exposed.
Dark (D)
- An incomplete dominant gene that is present in Black and many other dark angelfish. Commonly referred to as the Black gene, in error. An allele of Gold Marble, New Gold and Marble.
Gold Marble (Gm)
- A lightly marked marble that act similar to the Gold gene in crosses. An allele of Dark, Marble and Gold.
Halfblack (h)
- Recessive mutation whose penetrance may be influenced by modifiers. Environment will influence the expression of this gene.
Marble (M)
- An incomplete dominant gene that is an allele of Dark, New Gold and Gold Marble.
Gold (g)
- A recessive mutation that can be hidden in many strains. Originally referred to as New Gold. It is only one of a few gold mutations. Naja Gold and Hong Kong Gold (which are probably both lost to the hobby) are the other two. New Gold is an allele of Dark, Gold Marble and Marble.
Pearl (p)
- Not a color gene, but a recessive scale mutation that reflects light in a sparkling manner. Expressivity is environmentally influenced. The phenotype is commonly referred to as pearlscale.
Smokey (Sm)
- A dominant mutation. The phenotype of an angel that is homozygous for Smokey is known as a Chocolate.
Streaked (St)
- A dominant mutation that acts as a modifier of the Dark gene. It causes white or clear streaks in the fins and iridescent patches on the body in Blacks and others varieties containing the Dark gene. It exhibits variable expression. The streaks can be one or two fine lines or a bold white stripe. An underlying mottling can also be seen in (DD) and (Dg) that contain the gene for Streaked. There is some evidence that it is now expressing in some fish without the Dark gene.
Stripeless (S)
- An incomplete dominant that exhibits variable expressivity. It is not a color gene, but one that effects the expression of other color genes.
Veil (V)
- An incomplete dominat gene that affects the length of the fins of the angelfish. There may actually be several versions of this gene.
Zebra (Z)
- A dominant mutation that is an allele of Stripeless, therefore you cannot have a Blushing Zebra
Wild-Type (+)
- The allele that occurs most frequently in a population, or the one that is designated as normal, is called wild-type. For angelfish, this is commonly called Silver.
[edit] Common Phenotypes
Silver (+/+)
- The most commonly pictured form, this is also referred to as "wild-type", this type of fish does not contain any dominant color genes and at most a single dose of any recessive genes. Has silver body with 4 vertical black stripes. The stripes will fade and darken with mood. (Under stress will fade, darkest when breeding)
Gold (g/g)
- One of the hardiest and most attractive strains. Some will develop an intense orange crown. Gold is a recessive trait, like blue eyes in humans
Zebra (Z/+ or Z/Z)
- A Silver with extra stripes. A very popular strain.
Black Lace (D/+) / Zebra Lace (D/+ - Z/+)
- A Silver or Zebra with one copy of the Dark gene. This 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)
- Smokey with more of the dark pattern. Sometimes only the head is silver.
Halfblack (h/h)
- Silver with a black back half. Half black can be combined with other traits. (but not gold unfortunately) The pattern can disappear totally or partially if the fish is moved to conditions that are stressful to the fish.
Sunset Blushing (g/g S/S)
- The Sunset Blushing has two doses of gold and two doses of stripeless. They have a bright orange crown like a sunset. The body is mostly white in color, 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 is due to the red color of the gill covers as juveniles (you are seeing the blood vessels in the gills).
Koi (Gm/Gm S/S) or (Gm/g S/S)
- The Koi has a double or single dose of Gold Marble with a double dose of stripeless. They have a bright orange crown and some have orange on the fins. Body sometimes is all white, sometimes has a tangerine color.
Leopard (Sm/Sm Z/Z) or (Sm/Sm Z/+)
- The leopard is a very popular fish when young, having spots over most of their body. Most of these spots grow closer together as an adult so it looks like a chocolate with dots on it. (Smokey x Zebra)
German Blue Blushing (S/S)
- Some breeders feel there is a unique gene for this color variation that has not been described. The fish show a blue irridescent coloring and no stripes. The term blushing is due to the red color of the gill covers as juveniles (you are seeing the blood vessels in the gills).
Silver Gold Marble (Gm/+)
- A Silver angel with a single Gold Marble gene. A Gold Marble is light marbling pattern with patches of black that do not fade like the stripes.
Silver Ghost Gold Marble (Gm/+ - S/+)
- A Silver angel with Gold Marble pattern and the Ghost pattern. A Gold Marble is light marbling pattern with patches of black that do not fade like the stripes. Ghost is a mostly silver fish with just a stripe through the eye and tail. Sometimes the other hidden stripes will partially show, especially when the fish is excited.
Ghost (S/+)
- A fish with one copy of the stripeless gene. This results in a mostly silver fish with just a stripe through the eye and tail. Sometimes the other hidden stripes will partially show, especially when the fish is excited.
Gold Marble (Gm/g or Gm/Gm)
- A gold angel with black marbling. Depending on the actual genetics, you can go from a few black spots to a fish that is 75% black
Marble (M/+ or M/M or M/g or M/Gm)
- Standard marble is a black and silver marbled pattern. Black coverage varies from 30 to 80% black.
Black Hybrid (D/g or D/Gm)
- Cross a black with a gold, and you get black hybrids. A very vigorous black, that may look brassy when young. Does not breed true.
Gold PearlScale (g/g – p/p)
- The Gold PearlScale is a very attractive Gold angelfish, as the scales will reflect light from all angles. The PearlScale pattern develops at quarter size and peaks when mature.
Gold Marble PearlScale (Gm/g – p/p)
- The Gold Marble PearlScale is a very pretty gold angelfish with a light marbling pattern. The PearlScale will cause the scales reflect light from all angles. The PearlScale pattern develops at quarter size and peaks when mature.
PearlScale (p/p, gold pearl=g/g – p/p)
- The PearlScale varieties are very pretty fish as their scales reflect light from all angles. Gold, Silver, and Albinos are the most common PearlScale varieties, as the scales do not reflect well on darker fish. Pattern develops at quarter size and peaks when mature.
Black Ghost (D/+ - S/+)
- Charcoal grey body with no stripes. Fins are dark with the lace pattern.
Albino (a/a, gold albino=g/g – a/a)
- The true albino is a beautiful yellow-white fish with inverse stripes, and red eyes. Gold albinos will be a brilliant orange with pink pupils (silver eyes). Other albino varieties (Smokey, zebra, marble, etc.) are possible but uncommon.
[edit] Captive 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 gender of any individual until they are 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, some breeders have experienced a total refusal of the other mate to pair up with any other angelfish; others have had more success with subsequent mates. Both parents care for the young.
Depending upon aquarium conditions, P. scalare reaches sexual maturity at the age of six to twelve 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 ten days. Around the age of approximately three years, spawning frequency will decrease and eventually cease.
When the pair is ready to spawn, the pair will choose an appropriate medium upon which to lay the eggs and spend one to 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 will deposit a line of eggs on the spawning substrate, followed by the male who will fertilize the eggs. This process will repeat itself until there are a total of 100-600 eggs. The pair will take turns maintaining a high rate of water circulation around the eggs by swimming very close to the eggs and fanning the eggs with their lateral fins. In a few days, the eggs will hatch and the fry will remain attached to the spawning substrate. During this period, the fry will not eat and will survive by consuming the remains of their yolk sacs. At one week, the fry will detach and become free-swimming. Successful parents will keep close watch on the eggs until they become free-swimming. Once they begin swimming, the parents will clean them by sucking them into their mouths and spitting them out. At the free-swimming stage, the fry can be fed newly-hatched brine shrimp (artemia spp.); frozen or fresh.
P. altum is notably difficult to breed in an aquarium environment.
[edit] See also
- List of freshwater aquarium fish species
- Marine angelfish
- TheAquariumWiki's Article on Freshwater Angel Fish
[edit] References
- Pterophyllum (TSN 169844). Integrated Taxonomic Information System. Accessed on May 11, 2004.
- "Pterophyllum altum". FishBase. Ed. Ranier Froese and Daniel Pauly. April 2004 version. N.p.: FishBase, 2004.
- "Pterophyllum leopoldi". FishBase. Ed. Ranier Froese and Daniel Pauly. April 2004 version. N.p.: FishBase, 2004.
- "Pterophyllum scalare". FishBase. Ed. Ranier Froese and Daniel Pauly. April 2004 version. N.p.: FishBase, 2004.
