Xiphophorus montezumae (Jordan and Snyder 1900)

Etymology:

Xiphophorus: Greek, xiphos = sword + Greek, pherein = to carry

Montezumae Named after Montezuma the monarch of the Aztecs in the Aztec Triple Alliance

First description:

Jordan and Snyder, 1900

Notes on a collection of fishes from the rivers of Mexico, with description of twenty new species”. Bulletin of the U.S. Fish Commission. v. 19, pp. 115-147

Group:

Xiphophorus montezumae is one of nine northern swordtails and belongs to the Montezumae clade consisting of X. montezumae, X. nezahualcoyotl, X. continens

Type Locality:

Rio Verde [Rio Gallinas] near Rascon, San Luis Potosi, Mexico

Note: – Rio Gallinas is also known as Rio Frio

Distribution:

Northeastern Mexico, Tamaulipas, Northern Veracruz and San Luis Potosi

Populations:

Rio Gallinas system                                        Tamasopo

Rascon – includes El Quince and Rio ojo Frio

Arroyo La Cienega                                          Ojo Caliente

Arroyo Cienega Grande                                 Capuchin                    

Habitat:

Generally found in streams with strong currents over substrates of sand, gravel or rocks (Very rarely over mud or clay) with usually sparse or no vegetation.

Size:

Male 6cm female 7cm

Distinguishing characteristics:

A Large slender swordtail, The Capuchin strain of montezumae sword is the largest of the northern swordtails reaching a body length in excess of 75mm, the sword of the montezumae is generally ¾ to 1 ½ times its body length.

Colour/Pattern Variability:

Fish from the Rio Gallinas system can develop irregular black spots on their flanks that can extend onto the dorsal fin. These black spots / patterns are absent in the other populations.

Males from populations other than that in the Rio Gallinas (Rio Frio) have distinctive dorsal fin patterns.

A few males of all the populations develop a deep bronze to red coloration.

Tamasopo

Males have a bluish sheen to the body and can develop irregular black spots that form into patterns on the flanks which can extend into the dorsal fin. The tail fin possibly has a variable caudal blotch pattern and has a yellow sword with black edging.

Rascon.

Males have a bluish sheen to the body and can develop irregular black spots that form into patterns on the flanks which can extend into the dorsal fin. The tail fin has a yellow sword with black edging.

Ojo Caliente.

Males have a bluish sheen to the body with vertical stripes. The dorsal fin is light blue. A pale yellow tail fin sporting a pale blue sword edged with black.

Capuchin.

Males have a blue/green sheen to the body with a pale yellow tail fin sporting a pale blue sword edged with black. The dorsal fin is yellow and has two rows of black spots, a row along the base and a more irregular row through the center as well as other random spots. No development of block spots on the flanks.

Behaviour:

A peaceful active species

Husbandry:

Can be kept in a biotope aquarium with a gravel and rock base using a power filter to provide the current or a planted community aquarium for similar sized fish

X. montezumae is found at higher elevations than X. nezahaulcoyotl and therefore require a slightly lower temperature, Derek Lambert recommended 24 degrees

Breeding:

If well fed and maintained in an aquarium with plenty of hiding places, this species can be flock-bred, however it is recommended to remove the female to a heavily planted spawning tank about a week before birth.

Broods are produced on a monthly cycle with fry numbers of 25 on average.

Remarks

In the early collections X. nezahualcoyotl was often misidentified as X. montezumae and it is believed that all early work and analysis on X. montezumae was in fact carried out on X. nezahualcoyotl.

The profile for Xiphophorus montezumae includes the collection data that we are more familiar with in the UK, they are El Quince or Rio Ojo Frio. El Quince is a town on the Rio Ojo Frio south of the Nacimiento, (Headwaters or source), I have included these collections as part of the population known as ‘Rascon’. The initial data for the Rascon population came from the town Damian Corona roughly five miles south of El Quince, Damian Corona is several miles north of the town of Rascon.

References:

Rauchenberger, Kallman & Morizot: Monophyly and Geography of the Rio Panuco Basin Swordtails (Genus Xiphophorus) with Descriptions of Four New SpeciesDerek and Pat Lambert: Platies and swordtails