Cardinal tetra

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Cardinal tetra
Cardinal Paracheirodon axelrodi (3).jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Characiformes
Family: Characidae
Genus: Paracheirodon
Species:
P. axelrodi
Binomial name
Paracheirodon axelrodi
Synonyms [2]
  • Cheirodon axelrodiSchultz, 1956
  • Hyphessobrycon cardinalis Myers & Weitzman, 1956

The cardinal tetra (Paracheirodon axelrodi) is a freshwater fish of the family Characidae of order Characiformes. It is native to the upper Orinoco and Negro Rivers in South America. Growing to about 3 cm (1.2 in) total length, the cardinal tetra has the striking iridescent blue line characteristic of the genus Paracheirodon laterally bisecting the fish, with the body below this line being vivid red in color, hence the name "cardinal tetra". The cardinal tetra's appearance is similar to that of the closely related neon tetra, with which it is often confused; the neon's red coloration extends only about halfway to the nose, and the neon's blue stripe is a less vibrant blue.

The cardinal tetra is a very popular aquarium fish, but is less widespread than the neon tetra because until recently, it was difficult to breed in captivity. However, many breeders are now producing the fish; in most cases, one can determine if the cardinal tetra is bred or wild-caught due to damaged fins on wild-caught specimens. Some ichthyologists believe fishkeepers should continue to support the sustainable cardinal fishery of the Amazon Basin, since thousands of people are employed in the region to capture fish for the aquarium trade. If those fishermen lost their livelihoods catching cardinals and other tropical fish, they might turn their attention to engaging in deforestation. [3]

Taxonomy

American ichthyologist Leonard Peter Schultz described the cardinal tetra in 1956 as Cheirodon axelrodi. [2] The specific epithet honors ichthyologist Herbert R. Axelrod. Hyphessobrycon cardinalis is an obsolete synonym. The fish's common name, cardinal tetra, refers to the brilliant red coloration, reminiscent of a cardinal's robes. P. axelrodi is also often called the red neon tetra.

The species exists in a number of different color forms or phenotypes. A "gold" and "silver-blonde" form exists in the Rio Negro drainage that has less blue in the longitudinal stripe. The normal form from the Rio Negro drainage has a blue stripe, which extends to the adipose fin, while the Orinoco drainage phenotype has a stripe that stops posterior to the adipose. The Orinoco phenotype may represent a subspecies of P. axelrodi.

Description

The cardinal tetra (above) has more red on the underside than the superficially similar neon tetra (below). Cardinal tetra & neon tetra.jpg
The cardinal tetra (above) has more red on the underside than the superficially similar neon tetra (below).

The cardinal tetra has bright red ventral parts and an iridescent blue line that runs horizontally along its body. The characteristic iridescence of this and related fishes, such as the neon tetra, is a structural color, caused by refraction of light within guanine crystals that develop within special cells called iridocytes in the subcutaneous layer. The exact shade of blue seen depends on the viewing angle of the viewer relative to the fish - if the viewpoint changes so as to look at the fish more from below, the colour will change hue, becoming more deeply sapphire blue and even indigo. Change of viewpoint to one above the fishes, however, and the color becomes more greenish. Cardinal tetras appear to grow larger in captivity than they do in the wild. [4] They have a large stomach and small gut. [4]

Distribution and habitat

Cardinal tetras are found on the upper Orinoco and the Negro, which are located in Colombia and Venezuela and Brazil, respectively.

Ecology and behavior

Diet

The cardinal tetra forages in areas of slow-moving, shallow water. It is predominantly predatory, feeding on tiny animals found on underwater plants, roots, and leaf litter. Creatures commonly eaten include the larvae of chironomid midges and microcrustaceans such as water fleas (Cladocera) of the families Moinidae, Macrotrichidae, and Daphniidae, and copepods of the family Harpacticidae. Other organisms eaten include other fly larvae, insect eggs, rotifers, and testate amoebae. [4]

Reproduction

In the wild, the cardinal tetra swims upstream in large numbers to parts of its native river habitat completely enclosed above by rainforest canopy. Such waters are subject to heavy shading by the rainforest trees, and virtually no sunlight reaches them. Here, the fishes spawn in large aggregations. If the fishes are ready to spawn, the male pursues the female into fine-leaved plants; her fuller outline, which usually indicates the presence of ripe eggs within her reproductive tract, should be readily apparent at this point. If the female is ready, she allows the male to swim alongside her, and together, the pair release eggs and sperm.

Lifespan

The fish might also be effectively an annual species with a lifespan of just a single year in nature. It lives for several years in captivity. For those seeking to breed them in the aquarium, the best way to do so is by mimicking the same natural setup. A study conducted in Manaus, Brazil, subjected cardinal tetras to adverse water conditions for 96 hours. The fish perished at a low temperature of 19.6 °C (67.3 °F) and a high of 33.7 °C (92.7 °F), and pH below 2.9 or above 8.8. [5]

In the aquarium trade

A shoal of cardinal tetras in an aquarium Paracheirodon axelrodi school.jpg
A shoal of cardinal tetras in an aquarium

An entire industry is in place in Barcelos on the banks of Brazil's Rio Negro in which the local population catches fish for the aquarium trade. The cardinal fishery here is highly valued by the local people who act as stewards for the environment. The local people may not become involved in potentially environmentally damaging activities, such as deforestation, because they can make a sustainable living from the fishery. [3]

Between the years of 2006 to 2015, over 92,000,000 cardinal tetras were exported from the state of Amazonas, accounting for 64.57% of all ornamental fish exports from the state during this time. [6]

See also

Related Research Articles

<span class="mw-page-title-main">Characidae</span> Family of fishes

Characidae, the characids or characins, is a family of freshwater subtropical and tropical fish belonging to the order Characiformes. The name "characins" is an historical one, but scientists today tend to prefer "characids" to reflect their status as a, by and large, monophyletic group. To arrive there, this family has undergone much systematic and taxonomic change. Among those fishes remaining in the Characidae currently are the tetras, comprising the very similar genera Hemigrammus and Hyphessobrycon, as well as a few related forms, such as the cave and neon tetras. Fish of this family are important as food in several regions, and also constitute a large percentage of captive freshwater aquarium fish species.

<span class="mw-page-title-main">Neon tetra</span> Species of fish

The neon tetra is a freshwater fish of the characin family of order Characiformes. The type species of its genus, it is native to blackwater and clearwater streams in the Amazon basin of South America. Its bright colouring makes the fish visible to conspecifics in the dark blackwater streams, and is also the main reason for its popularity among freshwater fish hobbyists, with neon tetras being one of the most widely kept tropical fish in the world.

<span class="mw-page-title-main">Tetra</span> Common name for several species of fish

Tetra is the common name of many small freshwater characiform fishes. Tetras come from Africa, Central America, and South America, belonging to the biological family Characidae and to its former subfamilies Alestidae and Lebiasinidae. The Characidae are distinguished from other fish by the presence of a small adipose fin between the dorsal and caudal fins. Many of these, such as the neon tetra, are brightly colored and easy to keep in captivity. Consequently, they are extremely popular for home aquaria.

<i>Paracheirodon</i> Genus of fishes

Paracheirodon is a genus of freshwater fish in the family Characidae of the order Characiformes. The type species is P. innesi, the well-known neon tetra, and the Paracheirodon species are among the fishes known as tetras. All species of this genus are native to the Neotropical realm, occurring in the Orinoco and Amazon Basins in northern South America.

<span class="mw-page-title-main">Green neon tetra</span> Species of fish

The green neon tetra is a freshwater fish of the family Characidae of order Characiformes. It is native to the upper Orinoco and Negro Rivers in South America.

<span class="mw-page-title-main">Black neon tetra</span> Species of fish

The black neon tetra is a freshwater fish of the characin family (Characidae) of the order Characiformes. It is native to the Paraguay basin of southern Brazil. They are often found in the aquarium trade.

<i>Hyphessobrycon</i> Genus of fishes

Hyphessobrycon is a genus of freshwater fish in the family Characidae. These species are among the fishes known as tetras. The genus is distributed in the Neotropical realm from southern Mexico to Río de la Plata in Argentina. Many of these species are native to South America; about six species are from Central America and a single species, H. compressus is from southern Mexico.

<span class="mw-page-title-main">Rummy-nose tetra</span> Species of fish

The rummy-nose tetra is a species of tropical freshwater characin fish originating in South America, popular among fishkeepers as a tropical aquarium fish. One of many small tetras belonging to the same genus, it is on average 5 cm (2 in) long when fully grown. The fish is one of several very similar species including Petitella bleheri, and Petitella georgiae, and it is possible that more recently collected specimens available in the aquarium trade are members of one or other of these similar species. The common name applied to most of these fishes is "rummy-nose tetra", though other common names are in circulation.

Herbert Richard Axelrod was an American tropical fish expert, a publisher of pet books, and an entrepreneur. In 2005 he was sentenced in U.S. court to 18 months in prison for tax fraud.

George Sprague Myers was an American ichthyologist who spent most of his career at Stanford University. He served as the editor of Stanford Ichthyological Bulletin as well as president of the American Society of Ichthyologists and Herpetologists. Myers was also head of the Division of Fishes at the United States National Museum, and held a position as an ichthyologist for the United States Fish and Wildlife Service. He was also an advisor in fisheries and ichthyology to the Brazilian Government.

<i>Iguanodectes</i> Genus of fishes

Iguanodectes is a genus of freshwater fish found in tropical South America, with eight currently described species. They are all small tetras, none longer than 5 inches, and often have attractive silvery or striped scales, which makes them a target for the ornamental fish industry. Alongside the genus Piabucus, it is in the subfamily Iguanodectinae, which in turn is in the family Iguanodectidae. The genus Bryconops, which is also in Iguanodectidae, makes up a sister clade to Iguanodectinae.

<i>Petitella</i> Genus of fishes

Petitella is a genus of freshwater fish in the family Characidae of the order Characiformes.

<i>Piabucus</i> Genus of fishes

Piabucus is a genus of freshwater tetras in the family Iguanodectidae. All three species are found in South America, largely the Amazon and its major tributaries. None of them are longer than half a foot long, with the largest reaching a maximum size of 12.9 cm (5.1 in), and they are slender, with relatively deep chests and long pectoral fins. Their scales are pale or silvery, with lateral lines that stand out.

Project <i>Piaba</i> Fishery initiative

Project Piaba is a fishery initiative located on the Rio Negro tributary of the Amazon River. The program both promotes and researches sustainable aquarium pet fish collection and its impact on the environment. The name of the project comes from the Brazilian Portuguese word, piaba, which means "little fish", referring specifically to the cardinal tetra. Project Piaba is an ongoing project with annual research expeditions to the Rio Negro region. Because of the sustainable nature of the project, its slogan is "Buy a Fish, Save a Tree!"

<span class="mw-page-title-main">Iguanodectinae</span> Family of fish

Iguanodectinae is a subfamily of small freshwater fish in the family Iguanodectidae. They are most prominently found in the Amazon river basin and its major tributaries, but they are also known from the Tocantins, Orinoco, and Paraguay rivers. It has two genera, Piabucus and Iguanodectes. Some species in the subfamily are taken from the wild for aquariums, like the red- and green-line lizard tetras. There is minor, but ongoing, debate regarding its taxonomy.

Iguanodectes adujai is a species of freshwater fish that inhabits the rivers of South America. It largely prefers slow-moving blackwater habitats, though it has a slender body that suggests a further affinity for flowing water. It has a distinct lateral stripe in two horizontal sections, with bright-red at the top and yellow at the bottom.

<i>Iguanodectes geisleri</i> Species of fish

Iguanodectes geisleri, the red-line lizard tetra, is a species of freshwater fish from South America. It is a small species, largely herbivorous with some omnivorous traits, that prefers to live in schools and is partial to shallow waters, especially in blackwater habitats. Some aspects of its body plan are unique amongst its genus, including the position and length of the anal fin.

Iguanodectes spilurus, the green-line lizard tetra, is a small characiform fish from the rivers of South America. It is not a well-studied species, but research is available, including data from hobbyists that keep it as an ornamental fish. It has a distinct lateral stripe of reflective-green scales, and lacks any red markings therein; red is common in congeners' lateral stripes.

<i>Piabucus melanostoma</i> Species of fish

Piabucus melanostoma, sometimes called the chin tetra, is a small species of freshwater fish from the rivers of South America. It is the second-largest species of the genus, but still only reaches about 12 cm long. Occasionally found in captivity, it has an appealing iridescent-silver coloration. It is amongst the largest of fish still considered "tetras" in the aquarium hobby.

References

  1. IUCN (2023). "Paracheirodon axelrodi". IUCN Red List of Threatened Species . 2023: e.T164584363A164584373. doi: 10.2305/IUCN.UK.2023-1.RLTS.T164584363A164584373.en . Retrieved 11 December 2023.
  2. 1 2 Froese, Rainer; Pauly, Daniel (eds.) (2019). "Paracheirodon axelrodi" in FishBase . December 2019 version.
  3. 1 2 "Background about the Fishery and History | Project Piaba". projectpiaba.org. Retrieved 18 November 2017.
  4. 1 2 3 Walker, Ilse (2004). "The food spectrum of the cardinal - tetra (Paracheirodon axelrodi, Characidae) in its natural habitat". Acta Amazonica. 34 (1): 69–73. doi: 10.1590/S0044-59672004000100009 .
  5. Sarah Ragonha de Oliveira; Rondon Tatsuta Yamane Baptista de SouzaI; Érica da Silva Santiago NunesI; Cristiane Suely Melo de CarvalhoI; Glauber Cruz de MenezesI; Jaydione Luíz MarconII; Rodrigo Roubach; Eduardo Akifumi OnoI; Elizabeth Gusmão Affonso (2008). "Tolerance to temperature, pH, ammonia and nitrite in cardinal tetra, Paracheirodon axelrodi, an amazonian ornamental fish". Acta Amazonica. 38 (4): 773–779. doi: 10.1590/S0044-59672008000400023 .
  6. Tribuzy-Neto, Ivan Azevedo; Beltrão, Hélio; Benzaken, Zehev Schwartz & Yamamoto, Kedma Cristine (26 March 2021). "Analysis of the Ornamental Fish Exports from the Amazon State, Brazil". Boletim do Instituto de Pesca. 46 (4). doi: 10.20950/1678-2305.2020.46.4.554 . ISSN   1678-2305 . Retrieved 25 April 2024. Open Access logo PLoS transparent.svg