''Acanthicus'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of large, South American suckermouth armored catfishes native to the

Amazon Amazon most often refers to: * Amazon River, in South America * Amazon rainforest, a rainforest covering most of the Amazon basin * Amazon (company), an American multinational technology company * Amazons, a tribe of female warriors in Greek myth ...

and

Orinoco The Orinoco () is one of the longest rivers in South America at . Its drainage basin, sometimes known as the Orinoquia, covers approximately 1 million km2, with 65% of it in Venezuela and 35% in Colombia. It is the List of rivers by discharge, f ...

basins, and possibly in

Guyana Guyana, officially the Co-operative Republic of Guyana, is a country on the northern coast of South America, part of the historic British West Indies. entry "Guyana" Georgetown, Guyana, Georgetown is the capital of Guyana and is also the co ...

. The name ''Acanthicus'' is derived from the

Greek Greek may refer to: 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 of all kno ...

, ''akanthikos'' meaning thorny, spiny. Fish of this genus are known as lyre-tail plecos. These species are found in large rivers, primarily in areas with a rocky bottom and a moderate or strong current.

Species

There are currently 2 recognized species in this genus: * '' Acanthicus adonis'' Isbrücker & Nijssen, 1988 (adonis pleco, polka dot lyre-tail pleco) * '' Acanthicus hystrix''

Agassiz Jean Louis Rodolphe Agassiz ( ; ) FRS (For) FRSE (May 28, 1807 – December 14, 1873) was a Swiss-born American biologist and geologist who is recognized as a scholar of Earth's natural history. Spending his early life in Switzerland, he recei ...

''in''

Spix Johann Baptist Ritter von Spix (9 February 1781 – 13 March 1826) was a German natural history, biologist. From his expedition to Brazil, he brought to Germany a large variety of specimens of plants, insects, mammals, birds, amphibians and fish. ...

& Agassiz, 1829 (lyre-tail pleco) ''A. hystrix'' is also known as L155 by the

L-number The L-number system is a semi-scientific classification system of catfish based on photographs of shipments of tropical catfish of the family Loricariidae published by the German aquarium magazine DATZ (Die Aquarien- und Terrarienzeitschrift (The ...

system. Possibly

undescribed species In taxonomy, an undescribed taxon is a taxon (for example, a species) that has been discovered, but not yet formally described and named. The various Nomenclature Codes specify the requirements for a new taxon to be validly described and named. U ...

in the genus are L193 (

basin) and L407 ( Branco basin), but these may be variants of ''A. hystrix''.

Description

''Acanthicus'' are among the largest species in the family

Loricariidae Loricariidae is the largest family (biology), family of catfish (order Siluriformes), with over 90 genus, genera and just over 680 species. Loricariids originate from freshwater habitats of Costa Rica, Panama, and tropical and subtropical South A ...

. The largest officially measured ''A. adonis'' is in

standard length Fish measurement is the measuring of individual fish and various parts of fish anatomy, their anatomies, for data used in many areas of ichthyology, including Taxonomy (biology), taxonomy and fishery biology. Overall length Standard length (SL) is ...

(SL), and the largest officially measured ''A. hystrix'' is SL, but both appear to reach about SL. These fish are relatively slender, spiny Loricariids that lack an

adipose fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported only b ...

. The

caudal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported only ...

possesses long filamentous lobes on the upper and lower margins and is forked. The

pectoral fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish aquatic locomotion, swim. Apart from the tail or caudal fin, fish fins have no direct connection with the vertebral column ...

spines are extremely long. The entire dorsal surface of the head is covered in stout, sharp

odontode Odontodes, or dermal teeth, are hard structures found on the external surfaces of animals or near internal openings. They consist of a soft pulp surrounded by dentine and covered by a mineralized substance such as enamel, a structure similar to t ...

s. The odontodes form a sharp keel on the lateral plates and, in juveniles, there are few to no odontodes on the plates above and below the keel rows. The cheek odontodes are fairly thin, but numerous. Males may have more and longer cheek odontodes and greatly elongated odontodes on the pectoral fin spine. The colour of these fish is black, dark gray or medium to dark brown. Unlike ''A. hystrix'', juvenile ''A. adonis'' shows white spots; these are reduced with age and large adults may lack them.

In the aquarium

Both ''A. adonis'' and ''A. hystrix'' are sometimes kept in aquariums, and especially the densely white-spotted juveniles of the former species are regularly seen in the trade. They are opportunistic,

omnivorous An omnivore () is an animal that regularly consumes significant quantities of both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize ...

feeders that require well-oxygenated water. Their massive adult size and territorially aggressive behavior means that a very large tank is required. The territorial behavior is mostly aimed at other suckermouth armored catfishes and during disputes ''Acanthicus'' have even been known to kill ''

Pterygoplichthys gibbiceps ''Pterygoplichthys gibbiceps'' is a species of armored catfish native to Brazil, Ecuador, Peru and Venezuela where it is found in the Orinoco and Amazon basins. ''Pterygoplichthys gibbiceps'' shows all the characteristic features of its genus� ...

'' (itself typically considered a robust species). They have been bred in captivity.

References

{{Taxonbar, from=Q2290544 Ancistrini Fish of the Amazon basin Suckermouth catfish of Brazil Catfish genera Taxa named by Louis Agassiz Freshwater fish genera