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Swordtail - Common


Apr 2, 2004
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Common name: Swordtail

Scientific name: Xiphophorus helleri

Family: Poeciliidae

Origin: Southern Mexico and Guatemala

Maximum size: 4" or about 10cm (including tail)

Minimum Tank Size: Around 10-15 US gallons

Care: An easy fish for beginners. Needs a temp. of 72-73*F (22-23* C.) Enjoy well-planted aquariums with plenty of room for swimming. They live in loosely grouped schools. Usually Keep 1 male for every 2 females. These fish come in a variety of colors as many other livebearers do. Some varieties include the oringinal wild-type which has olive-green backs, greenish-yellow sides, yellow belly, and a red band. There are also lyretail swords and Hi-fin swordtail varieties. They should be housed with other peaceful community fish such as other livebearers, tetra, plecostomus, among many others.

Feeding: Takes Tropical flake, frozen, live, and freezedried foods.

Sexing: Most likely the easiest fish to sex. Male swordtails have the lower caudal fins extended into a "sword," hence the name. Usually as long as the body, but with new varieties, some may be 3-4 times as long! The females are more rounded and do not have a "sword"

Breeding: These fish give birth to live young. The parents tend to eat their young. At least a day or so birth takes place. (There is usually inteval of little over 30 days between broods,) the adults should be placed in a breeding trap though which the fry can escape. The young can take fine powdered food immediately, and should be fed small amounts about 3 X a day after that. The Females can store sperm for long periods of time so even if you have no males in your tank your females still might continue to give birth every 2 months or so. (These fish seem like they are always pregnant!)

Comments: Very interesting and easy to breed fish, although they have a short life span as being inbreed over years. This can be avoided by getting a trio or more of wild swordtails and house them in a highly planted tank with medium to hard water, good lighting, varied vegetation and plenty of free swimming space.


Nov 7, 2003
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just became an american *play dramatic music*
Here's pic of my swordtails since i don't see the above picture coming up. I would also like to add that males grow larger than 4" when you include the sword which can extend 3 inches so that brings the males total size to 7 inches.


My big neon blue/high fin female at 4 inches:


Livebearer fanatic
Retired Moderator
Jan 14, 2008
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Forsyth, Illinois, USA
A side note for all:

None of the pictures in this thread are true Xiphophorus helleri, they are all hybrids that have been bred for specific colors most often seen in platies. A true X helleri is what we would call a green swordtail in the hobby but often also has some black spots on its fins and body.


New Member
Sep 13, 2016
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Well, the description tells us only about the commercial fancy strains of swordtails derived from the Xiphophorus helleri. The fancy strains that we know nowadays are as already mentioned derived from the X.helleri. There were strains that were linebred after a mutation occured. And there are fancy strains that were mixed with influence of the X.maculatus (best known variety of the platy) and X.variatus (second best known variety of the platy). So, not all fancy swordtails are a hybrid between swordtail and platy, to be honest.
Then the name xiphophorus helleri... there are multiple wild strains that are considered being Xiphophorus helleri, but from different locations and phenotypically different. The only comparison these several helleris have is that they do belong to the green swordtails. But there are also multiple swordtail species that are not Xiphophorus helleri.
If we'd consider wild species and the water temperatures, northern swordtails do live in colder areas and therefore, they shouldn't be kept at somewhat higher temperatures but more moderate till even somewhat lower temperatures. This goes also for a decent number of wild platy species. It's more the southern swordtails and platies that prefer a bit higher temperatures. All the rest won't do well at higher rates.

In the description the following statement has been made: Most likely the easiest fish to sex. Male swordtails have the lower caudal fins extended into a "sword," hence the name. → The name "Swordtail" doesn't refer to the sword of the caudal but it refers officially to the gonopodium.

The max size of a male or female specimen does depend on the strain itself. There are a number of swordtails that stay moderate in size and there are swordtails species that will become large. And there are also dwarf species.

Below: A red brick male of a decent size.

Offcially, there are also wild swordtail species where males don't have a swordtail. There are also wild platy species that have a small bottomsword.
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pic of olive green swordtail pregnant fish

pregnant swordtail fish