Naked characin

{{Short description|Species of fish}} {{Speciesbox | image = Gymnocharacinus bergii, ilustración.jpg | status = CR | status_system = IUCN3.1 | parent_authority = Steindachner, 1903<ref name = "Cof genus">{{Cof genus|genus=Gymnocharacinus|access-date=11 November 2025}}</ref> | taxon = Gymnocharacinus bergii | display_parents = 2 | authority = Steindachner, 1903<ref name = "Cof genus"/> | synonyms = ''Gymnocharacinus bergi'' <br /><small>Steindachner, 1903</small> [orth. error] |status_ref=<ref name=iucn>{{cite iucn |author=Cussac, V. |author2=Quiroga, S. |author3=Kacoliris, F. |author4=Povedano, H. |author5=Crichigno, S. |author6=Becker, L. |author7=Baigún, C. |display-authors=3|date=2019 |title=''Gymnocharacinus bergii'' |article-number=e.T40695A119048712 |doi=10.2305/IUCN.UK.2019-2.RLTS.T40695A119048712.en |access-date=14 November 2021}}</ref> }}

The '''naked characin''' ('''''Gymnocharacinus bergii''''') is a species of freshwater ray-finned fish, a characin belonging to the suborder Characoidei. It is the only species in the genus '''''Gymnocharacinus'''''. This taxon has not been assigned to a particular family within the Characoidei and is considered to be ''incertae sedis'', i.e. its taxonomic affinities are, as yet, unclear.<ref name = "Cof genus"/> This taxon is the southernmost member of the family (together with some ''Cheirodon'' species from Chile) and it is endemic to the headwaters of a stream near Valcheta in northern Patagonia, Argentina, which flow from a thermal spring. It is endangered because of competition from the Uruguay tetra (''Cheirodon interruptus'') and predation from the rainbow trout (''Oncorhynchus mykiss''), both being invasive species within the naked tetra's restricted range.<ref name = iucn/> The naked tetra attains a maximum total length of {{cvt|7.5|cm}}. Adults have no scales.<ref name = FishBase>{{FishBase|Gymnocharacinus|bergii|month=April|year=2025}}</ref>

==References== {{Reflist}}

Category:Characoidei incertae sedis Category:Fish of South America Category:Fish of Argentina Category:Fish described in 1903 Category:Taxa named by Franz Steindachner Category:Taxonomy articles created by Polbot