Xiphophorus nezahualcoyotl - Back to Care Guide Page

    Water Conditions- Temp. 70-80 Degrees, pH 7.0-8.0, Water movement. Prefers at least 30 gallon tank
    Behavior- Peaceful community fish.
    Breeding- 10-40 young every 30 days, raise fry separately, can be fry eaters
    Size- 4 inches

    This line has been in this fishroom for over 15 years. Selectively bred for size and color, these are a gentle natured,
    very hardy, healthy, husky, distinctive swordtail. When the females are removed to have young, their spawns are generally
    robust and active. Unfortunately, there was a break in my keeping the line and it had begun producing smaller males.
    That trait is currently being bred out of them to get them back to a consistently large appearance.

    They do not do well as adults in a tank smaller than 20 gallons, and 30 gallons or above is better. They are a gregarious
    fish, constantly out in the open, and the amount of light does not matter, though plants should be provided for security.
    They must have aeration generated water movement, such as a box filter, or filtration in combination with an airstone or
    diffusion in the tank. They can get fairly large, and fully mature females will drop 30-40 young routinely. They are fry
    eaters, and the females should be moved to a heavily planted 5 or 10 gallon tank of her own to have her fry. Like most
    livebearers, she will generally drop her brood between sunup and noon. Remove the female as soon as young are spotted.
    Feed the young baby brine shrimp and finely powdered dry food and they will grow fairly quickly.

    The young show the unique black line spotting characteristic of the nezzy early, also possessed by the females that easily
    distinguishes them from the other wild or domestic swords. Where the females of some species seem indistinguishable, the
    nezzies are always easily identified, an important fact if you are keeping more than one species of swordtail.

    Adults will show the influence of live foods in greater size and color, particularly liking chopped earthworms, blackworms,
    brine shrimp etc. As the young mature, remove any males that begin sword development when only an inch or so long. You do
    not want them influencing the genetic makeup of your stock. The best males will not sex out fully until they are 2+ inches
    long, looking like large females, but without as pronounced a gravid spot. Some are seen in the video. Many of the males
    possess a “false gravid spot”, that with a little experience is easily distinguishable from a true gravid spot on the

    To continue the progress of the line, raise the sexes separately, choosing for the largest and best looking individuals
    of each generation.

    These have done best when kept in a 50 gallon show tank. The males will become very large and impressive, and the females
    should be chosen as breeders for their overall size and stocky body conformation.

    See other Care Guides Here