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Variety of Black molly

Lyretail molly

Poecilia sphenops

One of 4 varieties of Poecilia sphenops · See all varieties →

Also known as Red Lyretail Molly, Gold Lyretail Molly, Black Lyretail Molly

FreshwaterBrackishFish

Lyretail molly (Poecilia sphenops)

Varieties · Poecilia sphenops

See all 4 →

Care at a glance

Temperature
70–82°F
21–28°C
pH
7.0–8.0
Adult size
4.7 in
12 cm
Minimum tank
24 gal
90 L
Temperament
Mostly peaceful
Social behavior
Social
Swim level
Middle
Diet
Omnivore
Difficulty
Easy
Breeding
Livebearer · Easy
Rarity
Very common
Family
Poeciliidae

Overview

The lyretail molly is a finnage line rather than a color, so it stacks on black, gold, red and silver bodies. It is an easy fish for a calm community tank.

Did you know

The lyretail gene causes real trouble in a close relative, the lyretail swordtail. There the gonopodium overdevelops until the male cannot inseminate a female. An artificial insemination procedure has been published for that fish, while a hobby reference reports that lyretail mollies generally breed normally.

Caring for the lyretail molly

Keep lyretail mollies in a small group in a tank of at least 24 gal (90 L). Plants, open swimming space and steady warmth suit them. Their drawn-out top and bottom tail lobes tear and fray more readily than a short tail. Sharp decor shows on these fish first.

Give them hard, alkaline water at 70 to 82°F (21 to 28°C) and a pH of 7.0 to 8.0. They tolerate, and often appreciate, a little salt in the water. Lyretail mollies graze algae and need real plant matter, so feed a vegetable-based flake or pellet with some protein mixed in.

They are mostly peaceful and safe with other community fish, but a fin-nipping tank mate shows on their tails first. Keep more females than males to spread out the males' constant chasing. Females grow larger and rounder than males, and males carry a gonopodium, a modified anal fin used to fertilize females.

Lyretail mollies are livebearers that give birth to free-swimming young, and they breed easily. Crossing a lyretail to a short-finned fish puts the trait in a large share of the fry. That cross is how most lines are kept going.

Good to know

Lyretail draws the top and bottom of the caudal fin out past the middle, the same fin shape as a lyretail swordtail. In the related Xiphophorus livebearers, the trait is documented as dominant. Hobby breeders treat it the same way in mollies. Grade a lyretail by whether both lobes are even and intact, since ragged or one-sided tails are common.

In the wild

The lyretail molly came from a fin mutation in domesticated molly stock. It is one of several fin sports that breeders fixed and then bred into other color lines. Trade mollies already blend the short-finned and sailfin species, so a lyretail molly is a hybrid rather than one wild fish. Who first fixed it, and when, is not on record.

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Tank mates

The lyretail molly is a mostly 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 molly a different species from the black molly?

No. A lyretail molly is a variety of the black molly, Poecilia sphenops, and it wants the same tank, water and food as the species.

What size tank does a lyretail molly need?

A lyretail molly needs at least 24 gal (90 L). It spends most of its time in the middle.

What does a lyretail molly eat?

A lyretail molly grazes algae and needs real plant matter. Feed it a vegetable-based flake or pellet with some protein mixed in.

How big does a lyretail molly get?

An adult lyretail molly reaches about 4.7 in (12 cm).

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

Males carry a gonopodium, a modified anal fin they use to fertilize females. Females grow larger and rounder than males.

How does a lyretail molly breed?

A lyretail molly is a livebearer and breeds easily. Crossing a lyretail to a short-finned fish puts the trait in a large share of the fry, and that cross keeps most lines going.

Related species