Black Molly – Poecilia vetiprovidentiae

Black Molly is from the family of Poeciliidae, tooth carps that also include guppies, platy and sword tail. Their natural habitat is the Southern United States, Venezuela, Colombia, and Mexico. Black mollies were originally bred for aquariums in 1909 and since then have become one of the most popular fish over the years. This is due in large part to how little demands are required.

Black Lyretail Molly Source

Although mollies are available in many different colors, the black variant is still the most popular. Black mollies prefer to be in groups of at least four fish.

This fish is one of the easiest fish to care for and is an excellent fish for beginner aquarists. aLSO, The Molly can be bred quite easily and without much effort. Also, a female can give live birth to up to 100 fry after a gestation period of four weeks.

Black Molly Lifespan & Size

The black molly is quite simple to care for without much effort. If their basic needs are met, they can live 3 to 5 years. Also, they are quite a small fish, when fully grown will only be 1–2.5” (3-6cm) in size.


Male mollies have pointed dorsal and lower fins, and the females have rounded lower fins. They are live bearers which mean the eggs are kept inside their body, and they will give birth to live fry. It is important to keep the female separated from the other fish during pregnancy as additional breeding can cause deformities in the fry. Once she gives birth, she also needs to be separated from the fry because she will mistake them for food and eat them.

It is important that you pair the molly with a fish with the same type of characteristics, mollies pair well with guppies, platy, and swordtail. It is important not to pair mollies with Angelfish and Discus as these aggressive fish will stress, attack or kill mollies and their young.

Variety of shapes

The molly can be found in several shapes, the fork shape is one of the most common and resembles a guppy. The second is the lyretail that has longer fins on both the back and sides. finally, The third and final form is the “fantail”.

Variety of colors

The Molly is a particularly colorful, ornamental and diverse fish species. The black molly being the most popular. Some other popular colors include; silver, golden, and the Dalmatian Molly.



Black mollies are a peaceful fish. They do not protect their children as intensely as other livebearer fish. They prefer to stay in the middle to upper regions of a tank when swimming and searching for food between plants and rocks. Also, They are not schooling fish, but they prefer to live in groups of four to five for protection.


The Black Molly can be quite susceptible to diseases some common triggers for a disease are:

  • Water temperature lower than 72F (22°C)
  • Accumulation (slowly transitioning into a new tank)
  • Overpopulation (to many fish in a tank)
  • Stress (not enough shelters for hiding)


Black mollies are extremely popular for new aquarists; this is in part due to how easy it is to take care of them. The black molly prefers a vegetation diet, and they are especially good at eating algae. Fine flakes and other pellet foods are also good food as long as they do not sink quickly (they prefer not to eat off of the bottom of the tank). Although they are classified as herbivores, they will also eat mosquito larvae and brine shrimp.

Additionally, Molly’s are good at keeping your tank clean; they will eat algae off of plants and stones helping to prevent the early stages of an algae outbreak.

Black Molly Care

Aquarium size and temperature

Mollies need at least 10 gallons (37L) of water with lots of plant life. In the wild, they can be found in brackish water, so it is advisable that the water that is slightly salty. One teaspoon of slater per gallon is recommended. They also require a good filtration system and a tank cleaning every week.

In addition to this, black molly’s prefer a higher temperature of 77-82F (25-28°C). It is also important to remember that they are susceptible to temperature fluctuations and needs to be taken into consideration when changing the water of the aquarium.

In regards to the chemical characteristics of the water, it prefers a pH of 7 to 8 and moderately hard water.

10 gallon Tank ideally decorated for a molly Source

Plant Life

It is recommended that there is lots of plant life in your aquarium that offers a large range of hiding places, some recommended species also shown below are hornwort and hygrophila.

Hornwort Source
Hygrophila Source