Max Size: 10cm

Swordtail (Xiphophorus helleri)

Swordtails have to be one of the most popular aquarium fish. The Green Swordtail has been bred into several hybrid forms for the aquarium hobby due to its hardiness and adapting to many different water parameters, making them an excellent choice for beginner aquarists.

Swordtails are an active and peaceful fish that works well in a community tank with other small peaceful fish, and you can keep them in a species only tank. However, Swordtails can become nervous when kept with more extensive, boisterous fish, hiding away amongst the plants and decorations.

These fish live in groups but are not a shoaling fish and are best kept in groups of 5 or more, making sure there are more females than males as the males can be aggressive towards one another.

Swordtails' wild form is olive green in colour, with a red or brown lateral stripe and speckles on the dorsal and occasionally, caudal fins. These fish are best known for the unique, attractive tail that is yellow and edged in black below, although only males possess this.

Captive breeding has produced many colour varieties, including black, red, as well as various patterns for the aquarium hobby; still, they all originate from the wild green form.


Black Swordtail
Green Swordtail
Lyretail Swordtails
Wild Type Swordtail
Black Swordtail
Quick Facts
Scientific NameXiphophorus helleri
Other NamesRed, Green, Tuxedo, Koi, Lyretail, Black, Hi-fin, Neon
OriginsGuatemala, Honduras, Mexico
Aquarium LevelMiddle - Top
DifficultyBeginner - Intermediate
Best kept asGroups 5+
Lifespan3 - 5 years
Water Parameters
Water TypeFreshwater
PH7.0 - 8.5
GH12 - 30
65 - 82℉
18.3 - 27.8℃


In the home aquarium, the Swordtail will readily accept most good quality dried foods such as granules, flakes and sinking pellets. These modern food products have been developed to provide all adequate nutrition to maintain your fish's health and dietary requirements.

Providing additional foodstuffs such as live, frozen, and freeze-dried meals such as bloodworm, daphnia, and tubifex once or twice a week will provide additional benefits to your fish's health and well-being but is not a must for this fish.

It should be noted that bloodworms should only be given as an occasional treat and should not be used as the staple diet as they are difficult for fish to digest and can potentially cause blockages.

This fish is an omnivore in the wild, meaning it will consume some vegetable matter. Although most modern fish foods take this into account and include them in their products, you can still supplement your fish's diet with blanched vegetables such as spinach, broccoli, and zucchini. Ensure you do not overfeed your fish and remove any leftovers the following day.

Sexual Dimorphism

It is effortless to determine the male from female Swordtails. A Gonopodium's presence can distinguish males, a modified anal fin used to impregnate females during breeding.

Also, a male's caudal fin sticks out from its lower half, the extent of which may reach half of the body's entire length. The female caudal fin has no such protrusion. Also, females are usually much larger than males.

Other Livebearers of interest

Cardinal Brachyrhaphis(Brachyrhaphis roseni)
Dusky Millions Fish(Phalloceros caudimaculatus)
Humpbacked Limia(Limia nigrofasciata)
Merry Widow Livebearer(Phallichthys amates)
Mollies(Poecilia Sphenops)
Platies(Xiphophorus maculatus, Xiphophorus variatus)
View all Livebearers
Date Added: 22/01/2021 - Updated: 19/01/2022 14:56:06