Corydoras
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{{Taxobox
| name = ''Corydoras''
| fossil_range = Late [[Paleocene]] - Recent
| image = Corydoras semiaquilus 1.jpg
| image_width = 250px
| image_caption = ''[[Corydoras semiaquilus]]''
| regnum = [[Animal]]ia
| phylum = [[Chordata]]
| classis = [[Actinopterygii]]
| ordo = [[Siluriformes]]
| familia = [[Callichthyidae]]
| subfamilia = [[Corydoradinae]]
| tribus = '''Corydoradini'''
| tribus_authority = Hoedeman, 1952
| genus = '''''Corydoras'''''
| genus_authority = [[Bernard Germain Étienne comte de La Ville-sur-Illon La Cépède|Lacepède]], 1803
| type_species = ''[[Corydoras geoffroy]]''
| type_species_authority = Lacepède, 1803
| diversity_link = List of Corydoras species
| diversity = Over 150 valid species.<br>[[List of Corydoras species|List of ''Corydoras'' species]]
| synonyms =
*''Brochis'' (contested by some; see text)<br><small>[[Edward Drinker Cope|Cope]], 1871</small>
*''Cordorinus''<br><small>[[Constantine Samuel Rafinesque|Rafinesque]], 1815</small>
*''Hoplisoma''<br><small>[[William Swainson|Swainson]], 1838</small>
*''Chaenothorax''<br><small>Cope, 1878</small>
*''Gastrodermus''<br><small>Cope, 1878</small>
*''Osteogaster''<br><small>Cope, 1894</small>
*''Microcorydoras''<br><small>[[George S. Myers|Myers]], 1953</small>
}}
Members of the South American '''''Corydoras''''' [[genus]] are [[freshwater]] [[temperate]] and [[tropical]] [[catfish]] in the [[Callichthyidae|armored catfish]] family ([[Corydoradinae]] subfamily), and are commonly referred to as '''cory catfish''', '''cory cats''', or simply '''corys'''.
==Taxonomy==
The name ''Corydoras'' is derived from the [[Greek language|Greek]] ''kory'' (helmet) and ''doras'' (skin).<ref name=fishbase>{{FishBase genus | genus = Corydoras | year = 2006 | month = March}}</ref> ''Corydoras'' is by far the largest genus of [[Neotropics|neotropical]] fishes with over 142 species.<ref name="Axenrot"/> In addition, many variants exist.{{fact|date=July 2007}} It is the sole genus in the tribe '''Corydoradini'''.<ref name="Britto2003"/> ''C. difluviatilis'' is recognized as the [[basal (phylogenetics)|basalmost]] species of Corydoradini, exhibiting several [[plesiomorphy|plesiomorphic]] features compared to the other species of ''Corydoras''.<ref name="Britto2002"/><ref name="Britto2003"/> The [[type species]] for this genus is ''[[Corydoras geoffroy]]''.<ref name=fishbase/> Several hundred ''Corydoras'' species are not yet classified, but kept by [[aquarium|aquarists]]. These species are given ''C-Numbers'', originally devised by Hans-Georg Evers for the German fishkeeping magazine [[DATZ]] in 1993. In 2006, there were 153 C-numbers assigned, of which 32 had been assigned appropriate scientific names.
The ''C. barbatus'', ''C. macropterus'', and ''C. prionotos'' have been reclassified into the genus ''[[Scleromystax]]''.<ref name="Britto2003">{{cite journal|url=http://acd.ufrj.br/ppgzoo/orientadores/dados/Artigos%20Brito/Phylogeny%20Corydoradinae%20(Britto).pdf|title=Phylogeny of the subfamily Corydoradinae Hoedeman, 1952 (Siluriformes: Callichthyidae), with a definition of its genera|first=Marcelo R.|last=Britto|journal=Proceedings of the Academy of Natural Sciences of Philadelphia|volume=153|pages=119–154|date=December 2003|format=[[PDF]]|doi=10.1635/0097-3157(2003)153[0119:POTSCH]2.0.CO;2|year=2003}}</ref> ''Brochis'' had been differentiated from ''Corydoras'' due to the higher number of [[dorsal fin]] rays; however, ''Brochis'' has recently been suggested to be a [[synonym (taxonomy)|synonym]] of ''Corydoras''.<ref name="Britto2003"/> This is contested and has not been universally accepted. The [[sixray corydoras]] belongs in ''[[Aspidoras]]''.{{fact|date=July 2007}}
==Distribution==
The species of ''Corydoras'' usually have more restricted areas of endemism than other callichthyids, but the area of distribution of the entire genus almost equals the area of distribution of the family, except for [[Panama]] where ''Corydoras'' is not present.<ref>{{cite web|url=http://www.tolweb.org/Corydoras/15344|title=Corydoras|last=Reis|first=Roberto E.|authorlink=Roberto Esser dos Reis|date=1996-04-29|publisher=[[Tree of Life Web Project]]|accessdate=2007-07-12}}</ref> ''Corydoras'' species are distributed east of the [[Andes]] to the [[Atlantic]] coast, from [[Trinidad]] to the [[La Plata River]] drainage in northern [[Argentina]].<ref name="Axenrot"/> The genus is also widely distributed in South America from the [[Magdalena River]] basin, in [[Colombia]], and occurs in a variety of environments.<ref name="Britto2002">{{cite journal|journal=[[Copeia]]|year=2002|issue=4|pages=1006–1015|title=New Corydoradine Catfish (Siluriformes: Callichthyidae) from the Upper Paraná and São Francisco: The Sister Group of ''Brochis'' and Most of ''Corydoras'' Species|first=Marcelo R.|last=Britto|coauthors=Castro, Ricardo M. C.|doi=10.1643/0045-8511(2002)002[1006:NCCSCF]2.0.CO;2|volume=2002}}</ref>
==Description==
Species assigned to ''Corydoras'' display a broad diversity of body shapes and coloration.<ref name="Britto2002"/> ''Corydoras'' are small fish, ranging from 25 to 120 [[millimetre]]s (1.0–4.7 [[inch|in]]) [[fish measurement|SL]].<ref name="Axenrot"/>
==Ecology==
''Corydoras'' are generally found in smaller-sized streams, along the margins of larger rivers, in marshes and ponds.<ref name="Axenrot"/> They are native to slow-moving and almost still (but seldom stagnant) streams and small rivers of [[South America]] where the water is shallow and very clear.{{fact|date=July 2007}} Most species are bottom-dwellers, foraging in sand, gravel, or detritus.<ref name="Axenrot"/> The banks and sides of the streams are covered with a dense growth of plants, and this is where the corys are found. They inhabit a wide variety of water types but tend toward soft, neutral to slightly acidic or slightly alkaline [[pH]] and 5-10 degrees of [[hard water|hardness]]. They can tolerate only a small amount of salt (some species tolerate none at all) and do not inhabit environments with tidal influences.{{fact|date=July 2007}} They are often seen in shoals.<ref name="Axenrot"/> Most species prefer being in groups and many species are found in schools or aggregations of hundreds or even thousands of individuals, usually of a single species, but occasionally with other species mixed in.{{fact|date=July 2007}} Unlike most catfishes which are nocturnal, ''Corydoras'' species are active during the daytime.<ref name="Axenrot"/>
Their main food is bottom-dwelling insects and insect larvae and various worms, as well as some vegetable matter. Although no corys are piscivorous, they will eat flesh from dead fishes. Their feeding method is to search the bottom with their sensory barbels and suck up food items with their mouth, often burying their snout up to their eyes, one of the reasons a soft sand substrate is preferable.
In several species of ''Corydoras'', it has been observed that the fishes, after initial evasive reaction to threat, lay still; this is suggested to be a form of [[crypsis|cryptic behavior]]. However, it is also argued that most species do not have cryptic coloration nor freezing behavior and continue to exist.<ref name="Axenrot"/>
A few ''[[Otocinclus]]'' species (''O. mimulus'', ''O. flexilis'', ''O. affinis'', and ''O. xakriaba'') are considered to be [[mimic|Batesian mimic]]s of certain ''Corydoras'' species (''[[Corydoras diphyes|C. diphyes]]'', ''[[Corydoras paleatus|C. paleatus]]'', ''[[Corydoras nattereri|C. nattereri]]'', and ''[[Corydoras garbei|C. garbei]]'', respectively). These ''Corydoras'' species have bony plates of armor and strong spines as defenses, making them less palatable; by mimicking these species in size and coloration, ''Otocinclus'' avoid predation.<ref name="Axenrot">{{cite journal|url=http://www.ecology.su.se/pdfs/axenrot/fish.pdf|title=''Corydoras diphyes'' (Siluriformes: Callichthyidae) and ''Otocinclus mimulus'' (Siluriformes: Loricariidae), two new species of catfishes from Paraguay, a case of mimetic association|first=Thomas E.|last=Axenrot|coauthors=Kullander, Sven O.|journal=Ichthyol. Explor. Freshwaters|volume=14|issue=3|pages=249–272|date=October 2003|format=[[PDF]]}}</ref>
A unique form of insemination has been described in ''[[Corydoras aeneus]]''. 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 ''C. aeneus'', it is likely that this behavior is common in the genus.<ref name="Kohda1995">{{cite journal|url=http://www.springerlink.com/content/l62w27k5j077746g/fulltext.pdf|title=Sperm drinking by female catfishes: a novel mode of insemination|last=Kohda|first=Masanori|coauthors=Tanimura, Masayo; Kikue-Nakamura, Miyako; Yamagishi, Satoshi|journal=Environmental Biology of Fishes|volume=42|pages=1–6|year=1995|publisher=Kluwer Academic Publishers|format=[[PDF]]|doi=10.1007/BF00002344}}</ref>
==In the aquarium==
''Corydoras'' are well known among aquarists for its many ornamental species.<ref name="Huysentruyt">{{cite journal|url=http://www.fun-morph.ugent.be/Research/Publications/Publ35.pdf|title=Descriptive osteology of ''Corydoras aeneus'' (Siluriformes: Callichthyidae)|first=Frank|last=Huysentruyt|coauthors=Adriaens, Dominique|journal=Cybium|year=2005|volume=29|issue=3|pages=261–273|format=[[PDF]]}}</ref> They are well suited to [[tropical]] freshwater community aquariums, as they get along well with other species and are not at all aggressive. Corys are shy fish and it is recommended to keep them in groups of at least six as most species seem to form shoals in the aquaria (e.g. Paxton 1997). Corys are mostly bottom feeders, so they should be offered flake foods (which do sink), sinking pellets, and supplements of live and frozen foods, but care should be taken to prevent all the food from being eaten by the faster-moving fish at the higher levels of the tank.
Most corys prefer soft, acidic water. However, they can tolerate a wide range of water conditions. They do not do well in fish tanks with high [[nitrate]] levels. This ion leads to the infection of the [[barbels]], which will shorten and become useless. The barbels may also be affected by constant contact with a sharp [[Substrate (aquarium)|substrate]]. These are easy fish to keep, being peaceful, small, hardy, active, and entertaining. Occasionally they will dart to the surface, sticking their snout above the water for an instant, appearing to take a "breath" of fresh air. This behavior is perfectly normal and is not an indication that anything is wrong with the fish. However, if done in excess, this behavior may indicate poor water conditions.
Where investigated ''Corydoras'' sp. have been shown to be diurnal and [[crepuscular]] rather than nocturnal and activity can even peak at twilight (Paxton 1997). ''Corydoras'' are very good choices for a community aquarium, and are widely kept throughout the world. Their longevity in the aquarium is noteworthy; ''C. aeneus'' is said to have lived 27 years in captivity and 20 years is not too uncommon.
==References==
{{reflist}}
*{{cite web
| last = Evers
| first = Hans-Georg
| title = A system called “C-Numbers”
| accessdate = 2006-06-08
| url = http://www.corydorasworld.com/c_numbers
| language = English
}} (needs free account)
*{{cite book | title = A Complete Introduction to Corydoras and Related Catfishes | last = Burgess | first = W. E. | publisher = T.F.H. Publications | location = Neptune City, NJ | year = 1987 | id = ISBN 0-86622-264-2 }}
*Paxton, CGM (1997) Shoaling and activity levels in ''Corydoras'' catfish (Siluriformes: Callichthyidae) ''Journal of Fish Biology'' 51, 496-502.
==See also==
{{commonscat|Corydoradinae}}
* [[List of freshwater aquarium fish species]]
[[Category:Fishkeeping]]
[[Category:Corydoras| ]]
[[ca:Corydoras]]
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[[lt:Šarvuotieji šamukai (gentis)]]
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[[pt:Coridora]]
[[fi:Monniset (suku)]]