Xiphophorus couchianus

Xiphophorus couchianus  (Girard, 1859)

Affiliation: northern platyfish

IUCN status: extinct in the wild

Distribution: Historically endemic to the Monterrey metropolitan area, Nuevo León, Mexico; specifically restricted to the Río San Juan drainage. Found in Río Santa Catarina (Canyon La Huasteca) where the species got extinct in 1963; and later discovered also in several isolated locations between La Huasteca and Apodaca – where it got lost in 1990’s.

Known locations (existing/former): 0 / several

Habitat description: Inhabited clear, moderately flowing spring-fed pools and streams characterized by abundant submerged aquatic plants and dense riparian vegetation. The natural habitat was later severely altered by urbanization and water extraction.

Biotope reports:

• none yet

Description: Small (mostly < 4 cm) platyfish, greyish basic colour, typically lacking prominent dark blotches or macromelanophores; dorsal fins of males sometimes with yellow tint. Some black markings can be however present (see the photos below).

Variability: Limited variability known; generally uniform in coloration, lacking distinct melanophore patterns found in related species.

XWG status: actively managed

Represented in aquaria: moderately

Known issues:

• Low genetic variability, potentially due to bottleneck effects in captive populations.
• High susceptibility to diseases, notably bacterial infections (Mycobacterium spp.).
• Reproductive difficulties, including periods of unexplained reproductive cessation.

Known collections or populations:

• (Canyon) La Huasteca
• (Ojo de Agua de) Apodaca – Xiphophorus cf. couchianus?
• for overview of all historical locations, see this article by Andreas Tveteraas on our website

Remarks:

This species is managed within the project “Xiphophorus – Northern Platyfish” under the guidance of the Austrian Association for Vivaristics and Ecology (ÖVVÖ).

It is also managed in the Ex situ programme for the family Poeciliidae of the European Association of Zoos and Aquaria (EAZA).