| Naked characin | |
|---|---|
 | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Characiformes |
| Family: | incertae sedis |
| Genus: | Gymnocharacinus Steindachner, 1903 [2] |
| Species: | G. bergii |
| Binomial name | |
| Gymnocharacinus bergii Steindachner, 1903 [2] | |
| Synonyms | |
Gymnocharacinus bergi | |
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. [2] 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. [1] The naked tetra attains a maximum total length of 7.5 cm (3.0 in). Adults have no scales. [3]
