Xiphophorus couchianus (Girard 1859)

 

Meaning of Name After Lieutenant D.N.Couch. Described by C.Gerard in 1859 who made reference to Couch as 'a lover & cultivator of natural sciences'.
First Description

Girard C. 1859

Ichthyological notices, 41 - 59.
Academy of Natural Sciences Philadelphia. No.11: 113 - 122.
Size

Males: 30 mm, females: 40 mm.
Meristics

 
Karyotype

 
Sub-Genus

 
Group

Member of the group comprising andersi, couchianus, gordoni & meyeri.
Synonyms
  • Limia couchianus Girard 1859

Populations

  • Apodaca
  • Huasteca Canyon ( Nuevo León State, Mexico )

Male. Photo courtesy of Kjell Nilsson.

Female. Photo courtesy of Kjell Nilsson.
Type Locality

A female was used as a holotype measuring 41 mm. This was collected in the Rio San Juan in the area of Cadarecta & Monterrey, Nuevo León State, Mexico.
Distribution

Thought to be restricted to the Monterrey area of Mexico.
Habitat

Headwater streams, spring pools & rarely in sluggish flowing streams & ditches. The base is mostly clay & mud with a few areas of rock. Aquatic plants are quite dense with marginal plants near the banks.
Distinguishing Characteristics  
Colour/Pattern Variability In 1960 Donn E. Rosen reported details concerning a number of deep lying black spots on the caudal peduncle. He remarked that these were not present on all individuals but were known on populations from all areas in the hobby at that time. These markings appear to have been 'bred out' in successive captive bred generations.
These markings appear on X.meyeri.
History

Described by Girard in 1859 as Limia couchianus & later placed in Xiphophorus.
Breeding Notes

Considered a more challenging sp. They are secretive & hide away in planted areas.
Fairly tolerent of water conditions but a sudden change in pH will kill this sp. Water temperature 24°C. Gestation period is around 28 days (winter). Females are known to go through resting periods where no drops occur for several months. This is thought to be due to cooler temperatures in their natural habitat. An average air temperature of 12°C has been recorded in January with lows of -5°C. It should be noted that water from the springs feeding the habitat is warmer.
In areas where the spring water has ceased to flow the sp. has died out.
A short lived sp. only expected to reach 12 months of age. Older females are known to produce weak young which have a high mortality rate. Brood sizes are reported at an average of 20 but 40 has been recorded in young adult females.
Remarks

Commonly referred to as the Monterrey Platy.
In their natural environment this sp. is considered in danger of extinction due to pollution, habitat destruction & the introduction of Xiphophorus ophorus with which it interbreeds. Derek & Pat Lambert in 'Platies & Swordtails' reported that some pure populations exist in nature but their long term survival was doubtful.