The pinktail chalceus (''Chalceus macrolepidotus''),U.S. Fish and Wildlife Service.
Pinktail Chalceus (Chalceus macrolepidotus) Ecological Risk Screening Summary
'. 2018. also called the pinktail characin, is a species of freshwater fish of the family

Chalceidae Chalceidae, the tucanfishes, is a family of freshwater fish first described by Henry Weed Fowler in the year 1958. It is a monotypic family, home only to the genus ''incertae sedis'' ''Chalceus''. All members of the family inhabit areas of nort ...

found in South America. It is one of five fish in the genus ''

Chalceus ''Chalceus'' is a genus of fish that inhabits freshwater habitats in South America. Members can be found in the Amazon and Orinoco basins, as well as in the Guianas and various tributaries of the former. It is the sole representative of the fam ...

'', and is the type species of the genus.

Description

The pinktail chalceus is a small, light-colored freshwater fish with a tail that is usually dark red to pink and is much more intensely colored than the rest of the animal. It has large, noticeable scales and reaches 24.5 cm SL, making it the largest known member of ''Chalceus''. The smallest is ''Chalceus epakros''. ''

Chalceus epakros ''Chalceus epakros'' is a species of freshwater fish in the family Chalceidae, found in northern South America. It is a fairly recent addition to its genus, alongside the species '' C. guaporensis'' and '' C. spilogyros''. Description ''Chalc ...

'', before being classified, was regularly misidentified as either the pinktail chalceus or the yellowfin chalceus (''Chalceus erythrurus''). ''C. epakros'' and the pinktail can be told apart because the pinktail is uniform silvery in color, whereas ''C. epakros'' has a line down the middle of either side that reaches its caudal peduncle.

Etymology

The common name "pinktail chalceus" comes from its caudal fin, which is typically much more saturated in color than the main body. The specific name ''macrolepidotus'' means "large scale" in Latin, which is considered an accurate reflection of its scale size; the scales themselves are

cycloid In geometry, a cycloid is the curve traced by a point on a circle as it rolls along a straight line without slipping. A cycloid is a specific form of trochoid and is an example of a roulette, a curve generated by a curve rolling on another cu ...

. The original description gave it the common name "large-scaled chalceus". The genus name ''Chalceus'' comes from the Greek word ''chalkos'', which means brass or copper. This name was given based on the observation that the scales on the

type specimen In biology, a type is a particular wiktionary:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to a ...

were coppery ("sometimes golden") when preserved in alcohol.

Taxonomy

Upon description by French naturalist

Georges Cuvier Jean Léopold Nicolas Frédéric, Baron Cuvier (; 23 August 1769 – 13 May 1832), known as Georges Cuvier, was a French natural history, naturalist and zoology, zoologist, sometimes referred to as the "founding father of paleontology". Cuvier ...

in 1818, the pinktail chalceus was placed into the new genus ''Chalceus''. By way of

monotypy In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispe ...

, it ended up as the

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

therein. Since then, several additions and retractions have occurred, as well as a redescription of the genus in the year 2004, and there are now five accepted species in total, ''C. macrolepidotus'' included. The original scientific name given by Cuvier has remained its accepted scientific name. Synonyms include ''Brycon macrolepidotus'', ''Chalceus ararapeera'', ''Chalceus erythrurus'', ''Pellegrina heterolepsis'', and ''Creagrutus pellegrini''. The name ''Chalceus erythrurus'' has since been assigned to a different species in the genus altogether. The yellowfin chalceus, ''C. erythrurus'', was briefly classified as ''Chalceus macrolepidotus iquitensis'', a subspecies of the pinktail chalceus, by biologist Shoji Nakashima in 1941.

Habitat

The pinktail chalceus is found in well-oxygenated (fast-flowing) waters in South America; specifically, it is found in French Guiana, Guyana, and Suriname, inhabiting the Orinoco and Negro Rivers. ''C. epakros'' and the pinktail are the only two ''Chalceus'' species known to occur in

Guyana Guyana ( or ), officially the Cooperative Republic of Guyana, is a country on the northern mainland of South America. Guyana is an indigenous word which means "Land of Many Waters". The capital city is Georgetown. Guyana is bordered by the ...

. It has been non-natively established in Mexico as well, though it is not considered invasive by the Global Register of Introduced and Invasive Species (GRIIS).

Diet and behavior

The pinktail chalceus is a fast-moving and active fish that stays near the river's surface. It tends to cluster together in schools. Its diet generally consists of small invertebrates; when searching for food, it may leap out of the water to target a bug above the surface. It is notably skittish. This is a trait it shares with the yellowfin chalceus.

In aquaria

The pinktail chalceus is moderately popular in the aquarium trade, though it requires a larger aquarium than many prospective keepers have access to (55 gallons or above). It has enough of a reputation for jumping out of its tank (like its behavior in the wild) that sellers regularly warn buyers about it. This is more likely to happen if the pinktail is startled and does not have anyplace to take cover, such as plants or driftwood hideaways. Aquarists with adequate space to keep pinktails are advised to have a shoal larger than 6 to 8 specimens; anything lower, and squabbling is likely to happen. Because they are a fast and active species, the tank they live in doesn't need extraneous decor, but offering cover for them to hide in may make them more relaxed.

In popular culture

The pinktail chalceus is featured in the scuba diving video game '' Endless Ocean 2'' as one of several fish inhabiting the game's Cortica River area (a fictitious tributary of the

Amazon River The Amazon River (, ; es, Río Amazonas, pt, Rio Amazonas) in South America is the largest river by discharge volume of water in the world, and the disputed longest river system in the world in comparison to the Nile. The headwaters of t ...

, with a

confluence In geography, a confluence (also: ''conflux'') occurs where two or more flowing bodies of water join to form a single channel. A confluence can occur in several configurations: at the point where a tributary joins a larger river (main stem); o ...

at longitude 53° west). This is one of very few instances of a chalceus being depicted in a video game.

References

{{Taxonbar, from=Q3761027 Chalceidae Characiformes Taxa named by Georges Cuvier Fish of South America Fish described in 1818