Delicate Swordtail

Open encyclopedia reference

Xiphophorus cortezi, the delicate swordtail, is a species of poeciliid fish from Mexico.

Named after the Spanish conquistador Hernán Cortés, Xiphophorus cortezi was originally described in 1960 by Donn Eric Rosen as a subspecies of X. montezumae. It was well known in literature prior to the formal scientific description. The smaller males of X. cortezi are similar to the larger males of X. nigrensis, pointing to a close evolutionary relationship with this species too.

Adult size is variable and averages about 30 mm in standard length. The color of the male, especially the midlateral stripe, depends on the excitement of the fish and background shade of its environment. Some specimens kept in the laboratory for years have shown such silvery coloring that black markings became absent. Different patterns of black spots on the tail exist.

Xiphophorus cortezi is found in the upper Rio Panuco system in northeastern Mexico. Two congeners, X. pygmaeus and X. variatus, are found in the same section of Rio Axtla, a tributary of Rio Panuco, but the species are nearly always separated into different ecological niches.

Wikipedia contributors, Xiphophorus cortezi; see linked history · CC BY-SA 4.0 . Plain-text lead excerpt, at most 180 words; no infobox or later sections Retrieved 2026-10-05T07:24:54.450366+00:00. This reference remains separate from the taxonomic record.

Identity & source status

Scientific name

Xiphophorus cortezi Rosen, 1960

Name authority

Rosen, 1960

Common name

Delicate Swordtail

Rank

species

Accepted status

accepted

Kingdom

Animalia

Phylum

Chordata

Class

Teleostei

Order

Cyprinodontiformes

Family

Poeciliidae

Genus

Xiphophorus

Extinction status

Not supplied by this source

Source habitat flags: Marine: no · Freshwater: yes · Terrestrial: no. These do not form a complete habitat description.

Classification family tree

Nested taxonomic groups from the source. This is not a direct-ancestor chain, a dated evolutionary tree or a phylogenetic reconstruction.

1. domainEukaryota (Chatton, 1925) Whittaker & Margulis, 1978
2. kingdomAnimalia
3. phylumChordata
4. subphylumVertebrata
5. infraphylumGnathostomata
6. parvphylumOsteichthyes
7. gigaclassActinopterygii
8. superclassActinopteri
9. classTeleostei
10. orderCyprinodontiformes
11. familyPoeciliidae Bonaparte, 1831
12. subfamilyPoeciliinae Bonaparte, 1831
13. genusXiphophorus Heckel, 1848
14. speciesXiphophorus cortezi Rosen, 1960

Close classified relatives

These entries share the source’s genus, Xiphophorus. They are not necessarily the closest relatives established by molecular evidence.

Browse 299 records assigned to Poeciliidae.

Names & synonyms

Names explicitly linked to this accepted taxon in the source. Synonymy can change with revision.

Source literature & publication evidence

References attached to this source record, including nomenclatural citations where supplied. This is a selected bibliography; abbreviated citations remain in the source’s form.

1. Rosen, D. E. (1960). Middle-American poeciliid fishes of the genus Xiphophorus. Bulletin of the Florida State Museum, Biological Sciences, 5 (4): 57–242. https://doi.org/10.58782/flmnh.bnrr6484 Source fields: Taxon.tsv dwc:namePublishedIn, Taxon.tsv dcterms:references

Origins, evidence & remaining research

Name authority and publication references document nomenclature where the source supplies it. They do not establish evolutionary origins or the earliest fossil occurrence.

Specimen-level evidence, morphology, ecological research, phylogenetic studies, a comprehensive bibliography and a located literary passage have not yet been compiled for this record.

Dataset citation & attribution

This exact taxon in ChecklistBank · Catalogue of Life 2026-09-11

Catalogue of Life 2026-09-11; dataset 316321; doi:10.48580/dgz5n. https://creativecommons.org/licenses/by/4.0/ . Retrieved 5 October 2026.

Stable key: col:5CFP4. Classification follows source parent identifiers. English common names may vary by region.