Sam Borstein's Cichlid Page

Xiphophorus nezahualcoyotl
Rauchenberger, Kallman & Morizot, 1990

Northern Mountain Swordtail

Xiphophorus nezahualcoyotl
Above: A Male Northern Mountain Sword. Photo by Sam Borstein.


Genus- Xiphophorus= Swordtail (Greek).
Species-nezahualcoyotl= named for the Texcocan King, King Nezahualcoyotl.


The Northern Swordtail is an uncommon swordtail in the hobby, but a pretty one none the less. The fish can obtain some truly beautiful swords and also have very neat patterns on their body and fins.


This fish occurs in rivers and creeks of Mexico, specifically in the state San Luis Potosi.

Size, Maturity, and Sexual Dimorphism:

Size: Males- 2 inches, Females- 3 inches
Maturity: 2 inches
Sexual Dimorphism: Males have a sword while females are rounder and don't. Males have a gonopodium.

Nezi Sword
Above: A female Xiphophorus nezhualcoyotl. Photo by Sam Borstein.


This fish is easy to keep. About 5 or so adult and fry can be raised in a 15-20 gallon. The fish like water in the low 70's and alkaline. If you want to keep them in a community setting that is easy as well. They mix great with other non-aggressive species and even mild mannered cichlids.


These fish are not picky and will accept almost any flake or small pellet food.


Northern Mountain Swordtails are easy to breed. The females gestation is about a month, upon which 20-35 fry are born. The fry, although not large, pose no real issues when it comes to raising. It is a good idea to have some plants in the tank to allow cover for the fry. Fry growth is fast and they will gladly accept crushed flake or baby brine shrimp as a first food.


This is not your common swordtail, but overall an awesome fish. It seems to be very popular currently, but don't expect to find this fish in a pet shop. The nice demeanor and colors of this species make it a welcome aquarium resident.