{{Short description|Genus of fishes}} {{Automatic taxobox | fossil_range = {{fossilrange|Late Miocene|Present|refs=<ref>{{cite journal|author1=Bogan, S.|author2=Agnolin, F.L.|year=2020|title=First fossil of the Giant Armored Catfish ''Acanthicus'' (Siluriformes, Loricariidae) from the Late Miocene of Entre Ríos Province, Argentina|journal=Zootaxa|volume=4808|issue=3|pages=571–581|doi=10.11646/zootaxa.4808.3.11|pmid=33055970 |hdl=11336/153189|hdl-access=free}}</ref>}} | image = FMIB 38602 Acanthicus histrix Fort St Joaquim in the Distance.jpeg | image_caption = ''Acanthicus hystrix'' | taxon = Acanthicus | authority = Agassiz ''in'' Spix & Agassiz, 1829<ref name=Chamon2016>Chamon, C.C. (2016): Redescription of ''Acanthicus hystrix'' Agassiz, 1829 (Siluriformes: Loricariidae), with comments on the systematics and distribution of the genus. ''Zootaxa, 4088 (3): 395–408.''</ref> | type_species = '''''Acanthicus hystrix''''' | type_species_authority = Agassiz ''in'' Spix & Agassiz, 1829 }}
'''''Acanthicus''''' is a genus of large, South American suckermouth armored catfishes native to the Amazon and Orinoco basins, and possibly in Guyana.<ref name="Armbruster">{{cite web | url = http://www.auburn.edu/academic/science_math/res_area/loricariid/fish_key/Acanth/acansub.html | title = ''Acanthicus'' Spix, 1829 | author = Armbruster, J.W. | accessdate = 2007-07-21 | archive-date = 2016-03-03 | archive-url = https://web.archive.org/web/20160303201655/http://www.auburn.edu/academic/science_math/res_area/loricariid/fish_key/Acanth/acansub.html | url-status = dead }}</ref> The name ''Acanthicus'' is derived from the Greek, ''akanthikos'' meaning thorny, spiny.<ref name=fishbase>{{FishBase genus | genus = Acanthicus | year = 2016 | month = January }}</ref> Fish of this genus are known as lyre-tail plecos.<ref name=pchystrix>{{cite web | url = https://www.planetcatfish.com/common/species.php?species_id=217 | title = PlanetCatfish: Cat-eLog: Loricariidae: ''Acanthicus hystrix'' | accessdate = 1 March 2024}}</ref><ref name=pcadonis>{{cite web | url = https://www.planetcatfish.com/common/species.php?species_id=277 | title = PlanetCatfish: Cat-eLog: Loricariidae: ''Acanthicus adonis'' | accessdate = 1 March 2024}}</ref> These species are found in large rivers,<ref name="Armbruster"/> primarily in areas with a rocky bottom and a moderate or strong current.<ref name=Chamon2016/>
==Species== There are currently 2 recognized species in this genus:<ref name=Chamon2016/><ref name=fishbase/>
* ''Acanthicus adonis'' <small>Isbrücker & Nijssen, 1988</small> (adonis pleco, polka dot lyre-tail pleco) * ''Acanthicus hystrix'' <small>Agassiz ''in'' Spix & Agassiz, 1829</small> (lyre-tail pleco)
''A. hystrix'' is also known as L155 by the L-number system.<ref name=pchystrix/> Possibly undescribed species in the genus are L193 (Orinoco basin) and L407 (Branco basin), but these may be variants of ''A. hystrix''.<ref name=Chamon2016/>
==Description== [[File:Acanthicus hystrix.jpg|thumb|''Acanthicus hystrix'' always lacks white spots]] [[File:Acanthicus adonis1.jpg|thumb|Even in this relatively dark photo, the fine white spots in this medium-sized ''Acanthicus adonis'' can be seen (spots far more conspicuous in juveniles)]] ''Acanthicus'' are among the largest species in the family Loricariidae.<ref name="Armbruster"/> The largest officially measured ''A. adonis'' is {{cvt|30.5|cm|in}} in standard length (SL), and the largest officially measured ''A. hystrix'' is {{cvt|62.8|cm|in}} SL,<ref name=Chamon2016/> but both appear to reach about {{cvt|100|cm|in}} SL.<ref name="Armbruster"/><ref name=pcadonis/><ref name=SFhystrix>{{cite web| title=Acanthicus hystrix | url=http://www.seriouslyfish.com/species/acanthicus-hystrix/ | publisher=SeriouslyFish | accessdate=31 October 2017}}</ref>
These fish are relatively slender, spiny Loricariids that lack an adipose fin. The caudal fin possesses long filamentous lobes on the upper and lower margins and is forked. The pectoral fin spines are extremely long. The entire dorsal surface of the head is covered in stout, sharp odontodes. 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.<ref name="Armbruster"/>
The colour of these fish is black, dark gray or medium to dark brown.<ref name=Chamon2016/><ref name="Armbruster"/> Unlike ''A. hystrix'', juvenile ''A. adonis'' shows white spots; these are reduced with age and large adults may lack them.<ref name=Chamon2016/><ref name=pcadonis/><ref name=SFhystrix/>
==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.<ref name=pcadonis/><ref name=SFhystrix/><ref name=SFadonis>{{cite web| title=Acanthicus adonis | url=http://www.seriouslyfish.com/species/acanthicus-adonis/ | publisher=SeriouslyFish | accessdate=31 October 2017}}</ref> They are opportunistic, omnivorous feeders that require well-oxygenated water. Their massive adult size and territorially aggressive behavior means that a very large tank is required.<ref name=pcadonis/><ref name=SFhystrix/><ref name=SFadonis/> The territorial behavior is mostly aimed at other suckermouth armored catfishes and during disputes ''Acanthicus'' have even been known to kill ''Pterygoplichthys gibbiceps'' (itself typically considered a robust species).<ref name=pcadonis/> They have been bred in captivity.<ref name=pcadonis/>
==References== {{Reflist}}
{{Taxonbar|from=Q2290544}}
Category:Acanthicus Category:Hypostominae Category:Fish of the Amazon basin Category:Suckermouth catfish of Brazil Category:Catfish genera Category:Taxa named by Louis Agassiz Category:Freshwater fish genera