Pterophyllum is a small genus of freshwater fish 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, coloration which provides additional camouflage. Angelfish are ambush predators and prey on small fish and macro-invertebrates. 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.

P. scalare

The best known species of angelfish is Pterophyllum scalare. Its natural color is silvery with three brownish or black vertical stripes. It is very peaceful to the extent that it may be bullied by other more aggressive fish (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 up to 6 in (12″“15 cm) in length and up to 8 in (20 cm) high 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 75″“86°F (24″“30°C).

Average lifespan in an aquarium is 10 years, but there have been reported instances of individuals living twice as long. Freshwater angelfish are carnivores, meaning that they eat other fish, macroinvertebrates and other small animals. 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 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.

P. altum

“Pterophyllum altum”, (common name: Altum Angelfish or Orinoco Angelfish) occurs strictly in the Orinoco River Basin and the Upper Rio Negro watershed in Southern Venezuela, Southeastern Colombia and extreme Northern Brazil. Its natural color is also silver but with three brownish/red vertical stripes and red striping patterns into the fins. The species may show red spotting when mature and when aroused exhibits a black operculum spot. Characteristic of this species is an acute incision or notch above the nares. All true (pure) specimens show this trait, whereas commercial hybrids product of crosses to “Pterophyllum scalare”, that are occasionally performed by breeders to sell them as “Orinoco Altum”, will most likely not show this trait or show it to a much lesser degree. The true wild-caught Orinoco Altum is among the most challenging among tropical fish to breed in captivity. The species is the largest of the genus and specimens exceeding 19.69 in (50 cm) in height (from tip of dorsal to tip of anal fin) have been reported in the wild; in aquariums, specimens are known to have grown to 15.75 in (40 cm). Altum Angels are more frequently found in the well oxygenated, extremely soft waters of Upper and Middle Orinoco tributaries shed from the Guyana Shield Highlands, preferring a pH range between 4.5 to 5.8. These are very transparent blackwaters with almost nil conductivity. Temperature range in these waters is between 78.8 and 84.2°F (26 and 29°C). They are also found in the Atabapo River and Inirida River floodplain, down the Casiquiare and Guainia floodplain where the Rio Negro is born, before entering Brazilian territory. Unlike P. scalare (mentioned above) which prefer to spawn on plants, P. altum prefers to spawn on submerged roots and tree branches. This species is recommended for intermediate to advanced aquarists due to the detailed maintenance it requires for proper health.

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.

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.

Common Phenotypes

  • Silver (+/+) The most commonly pictured form, also referred to as “wild-type”, 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 (usually when under stress) and darken (usually when breeding) with mood.
  • Gold (g/g) Gold is one of the hardiest and most attractive strains. Some of these will develop an intense orange crown. Gold is a recessive trait, like blue eyes in humans.
  • Zebra (Z/+ or Z/Z) A Zebra is a Silver with extra stripes; this is a very popular strain.
  • Black Lace (D/+) / Zebra Lace (D/+ – Z/+) This is a Silver or Zebra with one copy of the Dark gene. This results in very attractive lacing in the fins. It is considered by some to the most attractive of all angelfish varieties.
  • Smokey (Sm/+) This is a variety with a dark brownish grey back half and dark dorsal and anal fins.
  • Chocolate (Sm/Sm) This is a Smokey with more of the dark pattern. Sometimes only the head is silver.
  • Halfblack (h/h) Halfblacks are Silvers with a black rear portion. A 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 doses of gold and two doses of Stripeless. The upper half of the fish exhibits orange on the good ones. 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 comes from the clear gill plates found on juveniles. You can see the pinkish gill underneath.
  • 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 express a variable amount of orange that varies with stress levels. The black marbling varies from 5%-40% coverage.
  • 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)
  • Blue Blushing (S/S) This is a wild-type angelfish that 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/+) This is a Silver angel with a single Gold Marble gene. This is a co-dominant expression of Silver and Gold Marble, so you see traits of both.
  • Ghost (S/+) A fish that is heterozygous for Stripeless. This 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) This is a gold angel with black marbling. 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 does. The marbling varies from 50% to 95%.
  • Black Hybrid (D/g or D/Gm) Cross a Black with a Gold, and you get Black Hybrids. It is a very vigorous black that may look brassy when young. They do not breed true.
  • Pearlscale (p/p) Pearlscale is a scale mutation. 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. It can be inhibited by stressful conditions. It is recessive, requiring both parents to contain the allele. It looks best on light colored fish like Gold, Gold Marble, Albino, Silver and Zebra. It’s difficult to see on dark fish and blushing angelfish.
  • Black Ghost (D/+ – S/+) These have the same description as a Ghost, with a darker appearance due to the Dark gene. They are very similar to a Black Lace without complete stripes. Ghosts generally have more iridescence than non-ghosts.
  • Albino (a/a) Albino removes dark pigments in most varieties. Some, like Albino Marble will 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 of Albino.

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 to up to 1200+ eggs, depending on the size and health of the female fish. 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 pectoral fins. In a few days, the eggs hatch and the fry 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. 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.