Astyanax jordani is a freshwater fish

Freshwater fish

Freshwater fish are fish that spend some or all of their lives in freshwater, such as rivers and lakes, with a salinity of less than 0.05%. These environments differ from marine conditions in many ways, the most obvious being the difference in levels of salinity...

of the characin family

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 (family Characidae

Characidae

The Characidae, characids or characins are a family of freshwater subtropical and tropical fish, belonging to the order Characiformes. The name "characins" is the historical one, but scientists today tend to prefer "characids" to reflect their status as a by and large monophyletic group at family...

) of
order

Order (biology)

In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...

 Characiformes

Characiformes

The Characiformes are an order of ray-finned fish, comprising the characins and their allies. Grouped in 18 recognized families, there are a few thousand different species, including the well-known piranha and tetras.-Taxonomy:...

, native to Mexico

Mexico

The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...

.
. It is called Cave Tetra (which is also used for the A. mexicanus subspecies mentioned above), or by its local Spanish

Spanish language

Spanish , also known as Castilian , is a Romance language in the Ibero-Romance group that evolved from several languages and dialects in central-northern Iberia around the 9th century and gradually spread with the expansion of the Kingdom of Castile into central and southern Iberia during the...

 name Sardina Ciega.

A blind cave fish, A. jordani is recently evolved from the Mexican tetra

Mexican tetra

The Mexican tetra or Blind Cave Fish is a freshwater fishof the characin family oforder Characiformes....

 (A. mexicanus). While it can be confused with the blind cave form of A. mexicanus, it evolved separately from the surface form, and is considered a different species.

(IUCN, however, treats it as a subspecies of A. mexicanus.)

This characin is listed on the IUCN Red List

IUCN Red List

The IUCN Red List of Threatened Species , founded in 1963, is the world's most comprehensive inventory of the global conservation status of biological species. The International Union for Conservation of Nature is the world's main authority on the conservation status of species...

 as Vulnerable on the basis of shrinking population and an acutely-restricted and diminishing area of occupancy. It is fairly resilient, however, having a population doubling time

Doubling time

The doubling time is the period of time required for a quantity to double in size or value. It is applied to population growth, inflation, resource extraction, consumption of goods, compound interest, the volume of malignant tumours, and many other things which tend to grow over time...

 of 15 months.

There are reports that it has been introduced to the Philippines

Philippines

The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...

.

Astyanax jordani was formerly classified as Anoptichthys jordani, the sole member of genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 Anoptichthys, and was first described by Carl Hubbs and William T. Innes

William T. Innes

William Thornton Innes III, L.H.D. was an American aquarist, author, photographer, printer and publisher. Innes was the author of numerous influential books and hundreds of articles about aquarium fish, aquatic plants and aquarium maintenance during the formative years of the aquarium hobby in...

. Anoptichthys hubbsi and Anoptichthys antrobius are junior synonyms.

Note that while this fish is often called "blind cave fish", that term normally refers more specifically to the blind cave form of A. mexicanus.