Black Lyretail Molly Fish (Poecilia latipinna)

black lyretail molly

Last updated on July 1st, 2022 at 02:14 pm

Poecilia latipinna, more commonly known as the black lyretail molly fish, is an aquarium fish species native to Mexico and Colombia. In its natural habitat, the black lyretail molly fish dwells in fresh water at temperatures between 72–79°F (22–26°C). The black molly fish grows to approximately 5 inches (13 cm) in length, with males growing slightly larger than females on average.

They are small fish of the livebearer family, Poeciliidae, typically growing to around 5 inches in length and sporting a tail fin that is longer than the body.

Black lyretail molly fish are one of the most popular varieties of aquarium fish, particularly among beginning aquarists who don’t yet have experience with finicky goldfish or more exotic fish varieties. Although black lyretail mollies can be found in tanks in just about any pet store, they are also easy to care for at home when you have the right supplies and know-how.

Origin and descriptions

black lyretail molly

Black lyretail mollies are native to Mexico and Guatemala but have also been introduced into parts of Florida. The males have a long dorsal fin on their backs that resembles a lyre, hence their common name.

They get their name from a number of different sources. The most popular reason for its common name of lyretail is because it has an extremely long tail that comes up past its dorsal fin. Another explanation for its name is that when viewed from above, it looks like a lyre.

In some areas, these fish are referred to as Texas lyretails or Amarillo lyretails because they were first discovered in Amarillo, TX by Dr. Robert Rush Miller in 1966. They have also been called wild-type guppies because their coloration closely resembles that of wild guppies.

It is thought that there may be several strains of black lyretail mollies with unique genetic mutations but further research needs to be done on them before any conclusions can be made.

Wrestling Halfbeak Fish (Dermogenys pusilla)

Species profile

The black lyretail molly fish belong to the family Poeciliidae, which contains over 100 species of live-bearing freshwater fishes. They are native to Central America and Mexico, but have been introduced into other areas of North America and are now considered an invasive species in some states.

Black lyretail mollies are popular aquarium fish, though they can be aggressive towards each other and should not be kept with smaller or more docile species. Males can reach up to 5 inches in length while females only grow up to 3 inches long.

Both sexes will generally display a dark brown/black coloration on their dorsal side with a lighter shade of brown on their ventral side. Their tail fin is edged in white and it has a unique shape that resembles a lyre. This type of tail is what gives them their name as lyretails.

These fish can live for up to 5 years if properly cared for, however, their life expectancy depends heavily on how well you maintain your tank water quality.

Scientific name

The scientific name of the black lyretail molly is Poecilia latipinna


Black lyretail mollies thrive in freshwater, saltwater, or brackish water aquariums, and can be kept with other similarly sized fish. They are active swimmers, so be sure to provide them with plenty of space and water circulation. Since they can be territorial, it’s best to keep only one per tank or divide a large tank into multiple compartments with plastic screens or dividers.

Black lyretail molly size

black lyretail molly

These species of fish can grow up to 5 inches (13 cm) in length.

Black molly tank size

The minimum recommended tank size for black lyretail molly is 20 gallons (76 liters).

Tank requirements

As tropical fish, they will be more active in warmer temperatures and become lethargic or stop eating at lower temperatures. They need clean water that has been treated with a dechlorinator, as chlorine and chloramines from tap water can kill them. This freshwater species should not be kept with other livebearers because of their aggressive nature.

Dalmatian Lyretail Molly (Poecilia latipinna)

A well-established aquarium will require very little maintenance, but new hobbyists must know how to read and adjust water parameters. The black lyretail molly (Poecilia latipinna) is a tropical fish that requires regular additions of iodine and salt, as well as an acidic water pH of 6.0–7.5.

The molly should be kept in tanks between 20–30 gallons with a sandy substrate, adding driftwood and rocks for hiding places when possible. The ideal temperature range for these fish is 77–82 degrees Fahrenheit.

Tank mates

Tank mates can include other mollies, guppies, platys, swordtails, and corydoras catfish.


black lyretail molly

Black lyretails are known to breed readily in captivity, making them excellent beginner fish. To ensure breeding success, keep only one male per tank and provide plenty of hiding spaces where females can lay their eggs. Eggs are laid on hard surfaces like glass or plastic plants; they should be removed after several days so they don’t get sucked into filters or eaten by other tank inhabitants.

It takes about four weeks for fry to develop from egg to juvenile stage. They should be fed live foods until they grow large enough to eat flake food. At about two months old, juvenile black lyretails can be added back into community tanks with adult fish of similar size and temperament.

Are they aggressive or peaceful?

The black lyretail molly fish is a peaceful, community fish. It will not fight with other black lyretail molly fish in its community tank but may be aggressive towards other non-mollies, such as tetras and angelfish. The black lyretail molly fish is a territorial species, so they are best housed by themselves if they are going to be kept in a smaller aquarium.

Black lyretail molly care

black lyretail molly

Black lyretail mollies are easy to care for and great beginner fish. They’re able to adapt well to new environments, have relatively few requirements, and will generally live long lives when properly cared for.

Poecilia sphenops (Marble Lyretail Molly)

Also known as black mollies, they are relatively easy to care for. They will accept most foods and water conditioners for tropical fish that can be purchased at a pet store. They are easy to feed since they will generally eat what is available from your other fish in your aquarium. A weekly dose of aquarium salt (1 teaspoon per 5 gallons of water) is recommended because it helps prevent diseases caused by parasites or bacteria that may affect your fish.

What they eat

Black lyretails are omnivorous feeders that consume both live and frozen foods. They enjoy fresh vegetables as much as they do live or frozen brine shrimp, bloodworms, and tubifex worms.

Along with a balanced diet of greens, fruits, and proteins from your local pet store, black lyretail mollies will thrive in many home aquariums.

Black lyretail molly lifespan

black lyretail molly

They can live for around 5 years if well taken care of, with proper water parameters.

Parasites and diseases

The black lyretail molly is susceptible to ich, velvet, and anchor worm. It is also prone to swim bladder issues. However, it can be treated with a salt bath or by adding aquarium salt to your tank at a rate of 1 teaspoon per 5 gallons of water. If you notice your fish acting strangely or swimming erratically, you should immediately remove it from your tank for treatment in a separate container until it recovers.


When it comes to aquatic life, predators can be a molly’s worst nightmare. Black lyretail mollies, for example, are victims of predation by other fish in both freshwater and saltwater habitats. Mollies also fall prey to birds in their natural environment. Humans can be predators as well; many fish fanciers consider black lyretails a popular choice for aquariums.

Some common predators are silver dollar, cichlids, black pacu, catfish, and piranhas.

Some of these fish will eat anything that fits in their mouth. Piranhas for example can eat up to 1/3 of their body weight in one sitting.

Datnioides pulcher (Siamese Tiger Fish)

Silver dollars are known to eat small fish whole and alive because they have a long digestive tract so they can digest them as they swim around.

Do they make good pets?

Yes! The Black Lyretail Molly Fish is a very active fish and spends most of its time in a school. It needs at least a 20 gallon tank with other mollies to keep it company. These little guys are known for jumping, so make sure you have a tight-fitting lid on your tank.

You can feed them flakes or live food. They enjoy being fed bloodworms, brine shrimp, or daphnia. You can also feed them lettuce leaves or spinach if they’re feeling picky. If you’re looking for an interesting pet that will be easy to care for, consider getting a black lyretail molly!