''Callichthys'' is a small

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include ...

catfish Catfish (or catfishes; order Siluriformes or Nematognathi) are a diverse group of ray-finned fish. Named for their prominent barbels, which resemble a cat's whiskers, catfish range in size and behavior from the three largest species alive, ...

in the Callichthyinae subfamily of the armored catfish family, and consists of 4 species from

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...

. The genus ''Callichthys'' is distributed in most freshwater drainages of

Taxonomy

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 ...

for this genus is '' Silurus callichthys''. The name ''Callichthys'' is derived from the

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

''kallos'' (beautiful) and ''ichthys'' (fish). 3 of the 4 species were described only relatively recently. The genus ''Callichthys'' is in need of taxonomic work, as it includes 13 nominal species but specimens of this genus are usually referred to as ''C. callichthys'' regardless of collecting locality. ''Callichthys'' is the most basal member of the subfamily Callichthyinae. Linnaeus described the first species in this genus in 1758, but three other members have been found since 1999.

Species

There are currently four recognized species in this genus: *''

Callichthys callichthys ''Callichthys callichthys'', the cascarudo, armored catfish, bubblenest catfish, hassar, or mailed catfish, is a subtropical freshwater fish belonging to the subfamily Callichthyinae of the family Callichthyidae. Taxonomy It was originally descr ...

'' (

Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement in 1761 as Carl von Linné Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, the ...

1758 Events January–March * January 1 – Swedish biologist Carl Linnaeus (Carl von Linné) publishes in Stockholm the first volume (''Animalia'') of the 10th edition of Systema Naturae, 10th edition of ''Systema Naturae'', the sta ...

) (Cascarudo) *''

Callichthys fabricioi ''Callichthys fabricioi'' is a tropical freshwater fish belonging to the Callichthyinae sub-family of the family Callichthyidae. The fish will grow in length up to 12.5 centimetres (5 in) SL. ''C. fabricioi'' is found in the trans-Ande ...

'' Román-Valencia, Lehmann A. &

Muñoz Muñoz ( or ) is a Spanish language, Spanish-language surname—with a Portuguese language, Portuguese-language variant (Munhoz (surname), Munhoz), from Basque "muinoa" (Hill), the surname got expanded during the Reconquista with massive settlements ...

, 1999 *''

Callichthys oibaensis ''Callichthys'' is a small genus of freshwater catfish in the Callichthyinae subfamily of the armored catfish family, and consists of 4 species from South America. The genus ''Callichthys'' is distributed in most freshwater drainages of South Am ...

'' Ardila Rodríguez, 2006 *''

Callichthys serralabium ''Callichthys serralabium'' is a tropical freshwater fish belonging to the Callichthyinae sub-family of the family Callichthyidae. Taxonomy It was originally described by Lehmann & Reis in 2004. The species name ''serralabium'' comes from the pre ...

'' Lehmann A. & R. E. dos Reis, 2004

Description

The genus ''Callichthys'' can be readily distinguished from other callichthyids by having the

coracoid A coracoid (from Greek κόραξ, ''koraks'', raven) is a paired bone which is part of the shoulder assembly in all vertebrates except therian mammals (marsupials and placentals). In therian mammals (including humans), a coracoid process is prese ...

s covered by skin and not exposed ventrally, the infraorbital bones also covered by skin, and the head highly depressed with less than 75% of the

cleithral This page is a glossary of architecture. A B C image:Porch of Maidens.jpg, The C ...

width (except sometimes in mature males).

Ecology

''Callichthys'' is normally found in large schools on the muddy bottoms of slow-moving rivers, pools, drainage ditches, and swampy areas. In water with low oxygen content, the fish are capable of utilizing atmospheric air by taking in a gulp of air at the surface of the water and passing it back to the hind gut. The walls of the gut are lined with tiny blood vessels into which the oxygen from the air can pass, similar to the function of true lungs. The remaining gasses pass out through the anus. When there is a severe drought, these air breathers are able to traverse short stretches of land seeking better conditions. The fish is also capable of making sounds, both grunts and squeaks.

In the aquarium

Spawning has been accomplished in the aquarium. ''Callichthys'' is a builder of bubblenests from plant parts, some bottom materials, and bubbles formed by a mouth secretion and air. The male forms a mass of bubbles about 20 cm (8 in) in diameter and 10 cm (4 in) high. During the time of construction, the female is actively chased away or ignored. When the nest construction is complete, the male will accept the female. The eggs (up to several hundred) are deposited into the nest and the male or the pair will actively protect the nest for about four weeks until the fry come out of the nest at the size of 2.5 cm (1 in).

References

* {{Taxonbar, from=Q1758830 Callichthyidae Catfish genera Taxa named by Giovanni Antonio Scopoli Freshwater fish genera