Astyanax mexicanus
(De Filippi, 1853) · speciesAt a glance
Sources11 archives
Databases and archives Astyanax mexicanus's data was compiled from.
WikipediaWikimedia Foundation14 languages↗
BioWikiNetmultilingual Wikipediamultilingual↗
GBIFGlobal Biodiversity Information Facility2 987 records↗
ENAEuropean Nucleotide Archive · EMBL-EBI7 eDNA detections↗
BOLD SystemsCentre for Biodiversity Genomics106 specimens↗
Open Tree of LifeOpenTreephylogeny backbone↗
GoaTGenomes on a Tree · Sangergenome & karyotype↗
NCBIUS National Library of Medicinegenome & karyotype↗
WikidataWikimedia Foundationstructured facts↗
Catalogue of LifeCOLtaxonomy↗
GLoBIGlobal Biotic Interactionsbiotic interactions↗Every layer below draws on the sources above — open one to explore it, or use ← → to move between tabs.
The Mexican tetra (Astyanax mexicanus), also known as the blind cave fish, blind cave characin, and blind cave tetra, is a freshwater fish of the family Characidae of the order Characiformes. The type species of its genus, it is native to the Nearctic realm, originating in the lower Rio Grande and the Neueces and Pecos Rivers in Texas, as well as the central and eastern parts of Mexico. Growing to a maximum total length of 12 cm, the Mexican tetra is of typical characin shape, with unremarkable, drab coloration. Its blind cave form, however, is notable for having no eyes or pigment; it has a pinkish-white color to its body (resembling an albino). This fish, especially the blind variant, is reasonably popular among aquarists. A. mexicanus is a peaceful species that spends most of its time in midlevel water above the rocky and sandy bottoms of pools and backwaters of creeks and rivers of its native environment. Coming from a subtropical climate, it prefers water with 6.5–8 pH, a hardness of up to 30 dGH, and a temperature range of 20 to. In the winter, some populations migrate to warmer waters. Its natural diet consists of crustaceans, insects, and annelids, although in captivity it is omnivorous. The Mexican tetra has been treated as a subspecies of A. fasciatus, but this is not widely accepted. Additionally, the blind cave form is sometimes recognized as a separate species, A. jordani, but this directly contradicts phylogenetic evidence.
No narrative description available for this taxon yet.
Size & morphology1
Life cycle & reproduction1
Habitat & environment2
Uses & economy1
Other traits1
A DNA barcode is a short, standardised stretch of genes that works like a fingerprint — enough to tell one species from another. Below is the molecular trace Astyanax mexicanus has left across the world's sequence archives.
At a glance
★ the standard DNA barcode for this group — the short region actually read to tell this species apart. The rest are extra genes sequenced along the way.
The complete instruction manual Astyanax mexicanus carries — its genome. We read it from three angles — how big it is, how the DNA is packed into chromosomes, and how completely it has been sequenced — and explain how to read each value as you go.
Genome sizehow big the whole instruction manual is
Measured in base pairs (bp) — the individual letters of DNA (human ≈ 3.2 Gb, a bacterium a few million). The chart places this genome on a logarithmic scale — each step to the right is ten times bigger — among reference organisms. Across species a bigger genome loosely tracks with larger cells, slower growth and lower-energy lifestyles (powered flight favours small genomes) — yet it does not imply more genes or a more advanced organism (the long-standing C-value paradox).
Sequencing statusassembly quality — how far to trust these numbers
Assembly level tells you how finished the sequence is — from fragmented contigs, through scaffolds, up to a full chromosome-level assembly. BUSCO % estimates completeness: the share of genes expected to be present that were actually found. These describe the data quality, not the organism.
How far back this lineage goes — and how we know. Everything here is measured in Ma, short for “mega-annum”: millions of years ago. The chart reads left to right like a calendar of the Earth, from the deep past on the left to today at the right edgetop to bottom like a core drilled through the Earth, from the deep past at the top down to today at the bottom.
At a glance
When this lineage existed
How to read this: the coloured strip along the bottomdown the left is the geological calendar — the standard epochs (Pliocene, Pleistocene…) every museum uses, shown so you can see which chapter of Earth's history this lineage lived in. This lineage is a young one, so the strip is zoomed in to epochs — the finer subdivisions inside a period. The orange marker is the DNA clock: DNA accumulates mutations at a roughly steady rate, so comparing this species' DNA with its relatives estimates when the lineage split off — independently of any fossil.
Record type2 987 records
Origin
Range
Wildobservation + sensor
Human sightings and records, or camera-trap / sensor detections — someone (or a device) saw or captured the species in the wild.
Museum / Voucheredphysical evidence
Backed by a physical specimen — a herbarium sheet, sample or voucher held in a collection. “Vouchered” means supported by material evidence, not just an observation.
Wildobservation + sensor
Human sightings and records, or camera-trap / sensor detections — someone (or a device) saw or captured the species in the wild.
Holding institutions17 of 34 geolocated
Institutions and collections holding physical, vouchered specimens of this species — click a row to fly to it on the map.
| Institution | Specimens |
|---|---|
| Texas Memorial Museum, Texas Natural History Collectionlocation not on record | 987 |
| München, DE | 246 |
| Mexico City, MX | 210 |
| Texas Cooperative Wildlife Collectionlocation not on record | 151 |
| Morelia, MX | 59 |
| Universidad de Navarra, Museum of Zoologylocation not on record | 51 |
| Ann Arbor, US | 48 |
| Sam Noble Oklahoma Museum of Natural Historylocation not on record | 46 |
| Centro de Investigaciones Biológicas, Universidad Autónoma del Estado de Moreloslocation not on record | 40 |
| Chicago, US | 33 |
| Juriquilla, MX | 33 |
| Cambridge, US | 19 |
| University of California San Diegolocation not on record | 17 |
| Champaign, US | 15 |
| Louisiana State University, Museum of Zoologylocation not on record | 13 |
| University of Alabamalocation not on record | 9 |
| ASUlocation not on record | 8 |
| Florida Museum of Natural History- Zoology, Paleontology & Paleobotanylocation not on record | 8 |
| CASlocation not on record | 5 |
| North Carolina Museum of Natural Scienceslocation not on record | 5 |
| New Haven, US | 4 |
| Washington, US | 4 |
| Mexico City, MX | 3 |
| Auckland, NZ | 3 |
| 2 | |
| FishBaselocation not on record | 2 |
| Ohio State University - Fish Division, Columbus, OH (OSUM)location not on record | 2 |
| Toronto, CA | 2 |
| Vancouver, CA | 1 |
| Southeastern Louisiana University, Vertebrate Museumlocation not on record | 1 |
| Museu de Zoologia da Universidade de Sao Paulolocation not on record | 1 |
| Montgomery, US | 1 |
| San Nicolás de los Garza, MX | 1 |
| University of Minnesota, James Ford Bell Museum of Natural Historylocation not on record | 1 |
Where the DNA of Astyanax mexicanus was picked up in samples of water, soil or air — nobody saw the organism, only its DNA left behind. A trace is a clue that the species was near, not a confirmed sighting.
Signal
Where its DNA was found
How strong is each trace?
Modelled climatemodelled
How to read this: each dot is one detection of this species' DNA in an environmental sample. The confidence meter weighs how many independent studies and places back up the signal — one detection in one study is a hint; many across several studies is solid. Records dated before 2008 (when eDNA methods began) are treated as likely mislabeled and left off the map.