Critically Endangered
Naked characin
Gymnocharacinus bergii
Naked characin is a characin in the family Characidae (order Characiformes) — Gymnocharacinus bergii, recorded as Critically Endangered.
The characin
The naked tetra attains a maximum total length of 7.5 cm (3.0 in).
Range and habitat
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, that 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.
Pins are Wikidata “endemic to” fields. Orange dots, when present, are GBIF occurrence tiles — survey bias included.
Habits
Characiforms school or hold small territories in Neotropical rivers. Many named tetras are known from one drainage that can be silted or dammed.
In crisis
Naked characin is Critically Endangered on this catalog because that is the IUCN category stored on Wikidata. Confirm the official criteria and any later count on iucnredlist.org.
Sources
Written for this catalog from the English Wikipedia article on Naked characin, Wikidata item Q3318187. Family and order context is original field-guide writing about the group, not a copied assessment of this one species. Wikipedia text is CC BY-SA. Not an IUCN assessment. Counts, when quoted, can change — confirm them on the recovery programme and on iucnredlist.org.



