TankBud

Variety of Green swordtail

Lyretail swordtail

Xiphophorus hellerii

One of 6 varieties of Xiphophorus hellerii · See all varieties →

Also known as Red Lyretail Swordtail

FreshwaterFish

Lyretail swordtail (Xiphophorus hellerii)

Varieties · Xiphophorus hellerii

See all 6 →

Care at a glance

Temperature
68–82°F
20–28°C
pH
7.0–8.0
Adult size
5.9 in
15 cm
Minimum tank
20 gal
76 L
Temperament
Peaceful
Social behavior
Social
Swim level
Middle
Difficulty
Beginner
Breeding
Livebearer · Easy
Rarity
Very common
Family
Poeciliidae

Overview

The lyretail swordtail has every fin extended, the sword included, splitting and trailing into a lyre shape. It is a peaceful, easy livebearer for a community tank.

Did you know

Hatcheries can keep a lyretail swordtail line going by artificial insemination. A published procedural guide to inseminating lyretail swordtails was written in 2003 for aquaculture producers.

Caring for the lyretail swordtail

Keep lyretail swordtails in a small group in a tank of at least 20 gal (76 L). They are active swimmers in the middle of the tank and like some length to cruise. Their finnage catches on rough decor and drags in strong current, so keep the layout smooth and the flow gentle. Planted edges with open space in the middle suit them.

Hard, alkaline water suits them, at 68 to 82°F (20 to 28°C) and a pH of 7.0 to 8.0. Feed a quality flake or pellet with some vegetable matter, and add the odd frozen treat.

Lyretail swordtails are peaceful community fish. A group with more females than males spreads out the males' attention. Males have a gonopodium, a rod-shaped anal fin, while females are larger bodied.

The gene that stretches the fins also lengthens the gonopodium, and most lyretail males cannot inseminate a female with an over-long one. That changes how a group behaves. Lines are held by crossing a normal-finned male to a lyretail female. The young are born live, and a female can store sperm for several broods from one mating, so give the fry plants to hide in.

Good to know

Hobby genetics references treat lyretail as a simple autosomal dominant, so one copy from either parent gives the finnage. Most lyretail swordtails are sold on a red body as the red lyretail. Males that do turn up with a normal gonopodium are called king lyretails. Lyretail platies and lyretail variatus are sold as well.

In the wild

The lyretail swordtail is a fin mutation maintained by aquarium breeders, not a wild form. No source consulted names the breeder, country or decade behind it, so it is a hobby line of uncertain origin.

Weekly picks

Tank mates

The lyretail swordtail is a peaceful, social species that keeps to the middle. These picks share a community profile with it, are safe together in both directions, and overlap on water type, temperature and pH.

Check the full mix in the stocking calculator

Common questions

Is a lyretail swordtail a different species from the green swordtail?

No. A lyretail swordtail is a variety of the green swordtail, Xiphophorus hellerii, and it wants the same tank, water and food as the species.

What size tank does a lyretail swordtail need?

A lyretail swordtail needs at least 20 gal (76 L). It spends most of its time in the middle.

What does a lyretail swordtail eat?

A lyretail swordtail eats a quality flake or pellet with some vegetable matter. Add the odd frozen treat.

How big does a lyretail swordtail get?

An adult lyretail swordtail reaches about 5.9 in (15 cm).

How can you tell a male lyretail swordtail from a female?

Males have a gonopodium, a rod-shaped anal fin that is often over-long in lyretails. Females are larger bodied.

How does a lyretail swordtail breed?

Lyretail swordtails bear live young, and a female can store sperm for several broods from one mating. Most lyretail males cannot inseminate a female, so lines are held by crossing a normal-finned male to a lyretail female.

Related species