Bronze corydoras

2025-10-09T19:23:47Z

191.110.88.223: /* In the aquarium */

{{Short description|Species of fish}}
{{Speciesbox
| name = Bronze corydoras
| image = Corydoras aeneus 2.jpg
| image_caption =
| status = LC
| status_system = IUCN3.1
| status_ref = <ref>{{cite iucn |author=Instituto Chico Mendes de Conservação da Biodiversidade (ICMBio) |author-link=Chico Mendes Institute for Biodiversity Conservation |year=2022 |title=''Corydoras aeneus'' |article-number=e.T186449A1813227 |doi=10.2305/IUCN.UK.2022-1.RLTS.T186449A1813227.pt |access-date=18 July 2024|lang=pt-br}}</ref>
| taxon = Osteogaster aenea
| authority = ([[Theodore Nicholas Gill|Gill]], 1858)
| synonyms = {{species list
|Hoplosoma aeneum |Gill, 1858
|Corydoras aeneus |(Gill, 1858)
|Corydoras venezuelanus |[[Hermann von Ihering|Ihering]], 1911
|Osteogaster aeneus |(Gill, 1858)}}
| synonyms_ref = <ref>{{Cof species|genus=Osteogaster|species=aenea|access-date=20 September 2025}}</ref>
}}

The '''bronze corydoras''' ('''''Osteogaster aenea'''''), also known as the '''green corydoras''', '''bronze catfish''', '''lightspot corydoras''' or '''wavy catfish''', is a species of [[freshwater fish]] in the armored catfish family, [[Callichthyidae]], often kept as an [[Freshwater aquarium fish|aquarium fish]]. It is widely distributed in South America on the eastern side of the [[Andes]], from [[Colombia]] and [[Trinidad]] to the [[Río de la Plata]] basin;<ref name=fishbase/> however, as presently defined it is a [[species complex]] and a [[Taxonomy (biology)|taxonomic]] review is necessary.<ref name=Tencatt2023>{{cite journal| last1=Tencatt | first1=L.F.C. | last2=Gomes | first2=V.d.C. | last3=Evers | first3=H.-G. | year=2023 | title=A new species of ''Corydoras'' (Siluriformes: Callichthyidae) from the rio Madre de Dios basin, Peruvian Amazon, with comments on ''Corydoras aeneus'' identity | journal=Neotrop. Ichthyol. | volume=21 | issue=2 | pages= | doi=10.1590/1982-0224-2023-0023 | s2cid=258460079 | doi-access=free }}</ref> It was originally described as ''Hoplosoma aeneum'' (based on a specimen from Trinidad) by [[Theodore Gill]] in 1858 and has historically also been referred to as ''Corydoras aeneus''.<ref name=fishbase>{{FishBase|genus=Corydoras|species=aeneus|year=2011|month=December}}</ref>

==Appearance and anatomy==
The adult size is 6½ cm for males and a slightly larger 7 cm for females (2½ to 2¾ inches).<ref>Dawes, John. "The Complete Encyclopedia of the Freshwater Aquarium". Interpet Publishing, 2001, p. 137.</ref> Females have a slightly higher body frame than males in accordance with their larger abdominal region. Their average [[life expectancy|life span]] is 10 years. It has a yellow or pink body, white belly, and is blue-grey over its head and back. Its fins are yellow or pink and immaculate. In common with most Corydoradini the dorsal, pectoral and adipose fins have an additional sharp barb and have a mild poison which causes fish which try to attack them to get stung. A brownish-orange patch is usually present on the head, just before the dorsal fin, and is its most distinctive feature when viewed from above in the stream. Their upper sides are often a greenish color, which is the reason another common name for this fish is the green cory.

==Ecology==
They are found in quiet, shallow waters with soft bottoms that can sometimes be heavily polluted by clouds of disturbed mud from the bottom, but it also inhabits running waters.<ref name=fishbase/> In its native habitat, it inhabits waters with a temperature range of {{convert|25|to|28|C|F}}, [[pH]] 6.0–8.0, and [[Hard water|hardness]] 5 to 19 [[DGH]].<ref name=fishbase/> Like most members of the genus ''Corydoras'', these [[catfish]] have a unique method of coping with the low [[oxygen]] content that prevails in such environments. In addition to utilizing their [[gills]] like any other [[fish]], they rapidly come to the surface of the water and draw air in through their mouth. This air is then absorbed through the wall of the intestine and any surplus air is expelled through the [[fish anatomy|vent]].<ref name=fishbase/> It typically stays in [[Shoaling and schooling|schools]] of 20 to 30 individuals.<ref name=fishbase/> It feeds on [[worm]]s, [[benthic]] [[crustacean]]s, [[insect]]s, and plant matter.<ref name=fishbase/>

===Reproduction===
[[File:Albino Cory Spawning.JPG|thumb|Albino ''Corydoras aeneus'' spawning]]
Reproduction occurs with the onset of the rainy season, which changes the water chemistry.<ref name=fishbase/> Females spawn 10–20 egg-clutches with multiple males at a time, but an entire egg clutch is inseminated by the sperm of a single male.<ref name="Kohda2002">{{cite journal |title=Male reproductive success in a promiscuous armoured catfish ''Corydoras aeneus'' (Callichthyidae) |first1=Masanori |last1=Kohda|last2=Yonebayashi |first2=Kanako |last3=Nakamura |first3=Miyako |last4=Ohnishi |first4=Nobuhiro |last5=Seki |first5=Satoko |last6=Takahashi |first6=Daisuke |last7=Takeyama |first7=Tomohiro |journal=[[Environmental Biology of Fishes]] |volume=63 |issue=3 |pages=281–287 |year=2002 |doi=10.1023/A:1014317009892|s2cid=41594346 }}</ref>

In laboratory observations, it was found that bronze corydoras have a unique method of insemination. When these fish reproduce, the male will present his abdomen to the female. The female will attach her mouth to the male's genital opening, creating the well-known "T-position" many ''Corydoras'' exhibit during courtship. The female will then drink the [[sperm]]. The sperm rapidly moves through her intestines and is discharged together with her eggs into a pouch formed by her pelvic fins. The female can then swim away and deposit the pouch somewhere else alone. Because the T-position is exhibited in other species than just ''O. aenea'', it is likely that they also exhibit this behavior.<ref name="Kohda1995">{{cite journal |title=Sperm drinking by female catfishes: a novel mode of insemination |last1=Kohda |first1=Masanori |last2=Tanimura |first2=Masayo |last3=Kikue-Nakamura |first3=Miyako |last4=Yamagishi |first4=Satoshi |journal=Environmental Biology of Fishes |volume=42 |issue=1 |pages=1–6 |year=1995 |doi=10.1007/BF00002344|s2cid=45023164 }}</ref> In the wild, eggs are laid on waterweeds.<ref name="Kohda2002"/>

Males do not form territories or compete over females; interference between males might only happen when two males present their abdomens simultaneously. On the other hand, females do not choose between males. Mating is more or less random; therefore, male reproductive success is directly related to courtship frequency.<ref name="Kohda2002"/>

The eggs of ''O. aenea'' exhibit a unique surface pattern with small [[Intestinal villus|villi]]-like protuberances which resemble attaching-filaments of teleost eggs. These structures allow the eggs to be adhesive and stick to a specific place or to each other. The presence of these structures may be related to the turbid habitat in which this species lives.<ref>{{cite journal |title=Adhesive structures in the eggs of ''Corydoras aeneus'' (Gill, 1858; Callichthyidae) |first1=Frank |last1=Huysentruyt |last2=Adriaens |first2=Dominque |journal=[[Journal of Fish Biology]] |year=2005 |volume=66 |issue=3 |pages=871–876 |doi=10.1111/j.0022-1112.2005.00647.x|citeseerx=10.1.1.492.9081 }}</ref>

==In the aquarium==
Bronze corydoras are likely the most popular Corydoradini species.<ref name=axelrod>{{cite book | title = Exotic Tropical Fishes | last = Axelrod | first = Herbert, R. | author-link = Herbert R. Axelrod | publisher = T.F.H. Publications | year = 1996 | isbn = 978-0-87666-543-5}}</ref> It is annually bred and shipped in large quantities all over the world.<ref>{{cite journal|url=https://www.researchgate.net/publication/228671375 |title=Descriptive osteology of ''Corydoras aeneus'' (Siluriformes: Callichthyidae)|first=Frank |last=Huysentruyt|author2=Adriaens, Dominique|journal=Cybium|year=2005|volume=29|issue=3|pages=261–273 |via=ResearchGate}}</ref> It is easily bred and is produced in commercial quantities in the [[United States]], Europe, and [[Singapore]]. Most of the available fish are therefore captive-bred strains. Wild imports are reported to be less easy to breed.{{citation needed|date=September 2014}}

They are a hardy and useful aquarium fish despite having a coloration that is by no means striking or unusual. Many [[aquarist]]s are fascinated by the habits of these fish. They ceaselessly comb the bottom of the aquarium for food and therefore disturb it slightly, sending up [[detritus]] and waste material that has settled loosely on the bottom. They prefer being kept in [[Shoaling and schooling|groups]] of 5 or more, being sociable fish and are ideal fish for a [[community tank]].<ref name=fishbase/> Other ''[[Corydoras]]'' species can be placed in the same aquarium, and despite the strong resemblance many species bear to one another, each one tends to school with only their own kind.

''Osteogaster aenea'' is not particular about the composition of the water. Adequate conditions are a temperature range of {{convert|20|to|28|C|F}}, pH of 6.0–8.0, and hardness of 2–30 [[DGH]]. The water should have no salt added to it.<ref name=axelrod/> A fairly dense growth of plants with a number of possible hiding places is greatly appreciated. Corys are easy to feed; they are [[omnivore]]s and can eat a wide variety of flake and pelleted food, as well as many live and frozen foods.

When properly cared for, bronze corydoras are considered fairly easy to breed. After the breeding process, the female glues the [[Egg (biology)#Fish eggs|eggs]] to her chosen surface, using her pelvic fins to deposit them. After several acts of spawning, which span a total of two to three hours, one female will have produced up to 200 eggs. Frequently, a female will spawn with two males, as one male cannot always sufficiently fertilize all the eggs. Once deposited, the eggs gradually grow darker in color over the course of around 3-7 days. When they are fully developed, they will turn dark brown and hatch. The newly hatched fry will generally keep to the bottom of the tank, feeding on detritus and any small food they find. The parents may spawn again within two to three weeks.

[[File:Corydoras Albino.jpg|right|thumb|Albino corydoras]]

===Albino corydoras===
The albino corydoras is an [[albino]] variety of the bronze corydoras that has been developed for the aquarium trade, with a pale pink or orange body and red eyes. It is physically similar to normally-colored individuals, although some breeders report that the fry are a little slower to develop.<ref name="How long do cory catfish live">{{cite web |last1=Davis |first1=Ben |title=How long do cory catfish live? |url=https://www.mvorganizing.org/how-long-do-cory-catfish-live/|archive-url=https://web.archive.org/web/20211201160419/https://www.mvorganizing.org/how-long-do-cory-catfish-live/|website=mvorganizing.org |archive-date=1 December 2021|access-date=8 November 2021}}</ref> Others say that the albinos are practically blind and that the males are somewhat sterile, although this may be due to extensive inbreeding.<ref name="How long do cory catfish live"/> Albino bronze corydoras are frequently injected with bright dye (via a needle) and sold in aquariums. This controversial practice is known as "[[painted fish|painting]]" or "juicing" fish.

==See also==
*[[List of freshwater aquarium fish species]]

==References==
{{Reflist|30em}}

==Further reading==
* {{cite book | title = A Complete Introduction to Corydoras and Related Catfishes | last = Burgess | first = Dr. Warren E. | publisher = T.F.H. Publications | location = Neptune City, NJ | year = 1987 | isbn = 978-0-86622-264-8 }}
* {{cite journal | last = Zukal | first = Rudolf | title = Breeding ''Corydoras aeneus'' | journal = Tropical Fish Hobbyist |date=May 1982 | pages = 9–10 }}

==External links==
* [http://www.bimbel.de/artikel/artikel-40.html Corydoras from egg to larva] (German)

{{Commons category|Corydoras aeneus}}

{{Taxonbar|from=Q741269}}

[[Category:Corydoras]]
[[Category:Taxa named by Theodore Gill]]
[[Category:Fish described in 1858]]

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Bronze corydoras