The Complete Guide to Molly Fish Breeding Cycle

Molly fish are one of the most colorful freshwater fish. These brightly colored mollies make great additions to any aquarium and come in many different varieties. Since this fish is prevalent, many fish keepers want to breed them. The breeding cycle of Molly fish is a fascinating question among them.

The breeding cycle of Molly fish is a complicated process that requires both the molly fish, male and female, to be healthy. Therefore, the first step in breeding mollies is purchasing two compatible molly types. Although many pet stores will try to sell you mollies of different colors, it’s best to buy mollies of the same color type.

In this post, I will try to explore more about the breeding cycle of Molly fish. Hopefully, this post will be informative enough for molly fish keepers.

What Type Of Fish Is Molly Fish?

Molly fish belong to the family of Pocelidiae. Molly fish can be present in and around Mexico and Florida and throughout South and Central America. These fish have a high reproductive rate and breed throughout the year.

Molly fish come from slow-moving waters such as ponds or lakes that host vegetation for them to lay diploid eggs. These diploid eggs fertilize externally and produce fry. Molly fish can grow to a length of up to four inches within its lifespan of three to five years.

The nice thing about molly fish is that they come in many different colors, such as red or black spots on their dorsal fin with a white or yellow body. Molly fish eat water fleas, plankton, and algae in the wild. But domesticated Mollies can easily survive on flake food if you do not want to feed live foods.

Breeding Cycle Of Molly Fish

Molly fish breeding cycle is simple and easy. They are live-bearing species that give birth to their young ones after a gestation period of eight weeks. During this time, the female will carry the eggs inside her body until they finally hatch in about 24 hours. 

Molly fish are not picky when it comes to breeding. They can mate with any male of their choice. Usually, the breeding cycle of Molly fish starts during the warmer months of spring and summer. This is because they require a temperature ranging from 68 to 75 degrees Fahrenheit, around 20 – 23°Celsius.

After laying about 40-100 diploid eggs, males fertilize them externally. These eggs will then evolve into Molly fish for one to two days in a favorable condition. So, you can quickly breed these fish by placing them in separate tanks consisting of the male and female until they reproduce naturally.

How Does Molly Fish Breed?

Mollies are livebearers, which means they have a placenta and produce their young alive rather than lay eggs. This is another reason why you should keep these fish in pairs or small groups.

Usually, Molly fish can produce several broods in a year, but it varies with water temperature, time of the year, and feeding. Molly fish will give birth to their fry at around two inches long.

Some Mollies breed by laying eggs. So, you will notice them laying eggs outside the body. Molly fish will lay their eggs on plants, rocks, and sometimes in your tank filter box. When a female is ready to give birth, she usually becomes very active at night when it’s dark or under dim light conditions.

At this time, you may see her swimming back and forth with apparent agitation above the aquarium floor close to a vertical surface such as a rock, plant, or aquarium glass. Molly fish will often lay their eggs on plants with broad leaves where they can hide from predators and have an easy source of food nearby after birth.

When Do Molly Fish Start Breeding?

The Molly fish breeding cycle starts when they reach sexual maturity, two to three years after hatching. Molly is a livebearer, so the female will give birth around 60 days after mating with male Molly.

Do not worry if you do not have a male partner because Molly can breed independently by laying eggs without fertilization from a male Molly. But for this, Mollies must have some stored sperms in their body. Therefore, Molly fish will not show signs of pregnancy, but you should know that it takes around four to six weeks for the female to give birth, which means she is pregnant at mating time.

Can You Breed Molly Fish In Home Aquarium?

Molly fish are one of the most popular aquarium species. If you are careful enough and provide them the best living conditions, they can reproduce and create a lot of generations. Molly’s fish breeding cycle begins with male molly fish that will court female ones to mating several times during one day.

So, some tips for breeding Molly fish at home are:

Select Compatible Male And Female

Molly fish are very selective when it comes to choosing their life partner. So, you should never keep two Mollies of opposite genders in the same tank. They might become a couple and will not show interest in mating with other fishes available.

Maintain A Healthy Tank

Molly fish are susceptible to poor water quality. So, you must keep the aquarium clean and maintain nitrate levels below 0.25 ppm at all times. In addition, Molly should breed in a tank of 20 gallons capacity with all crucial water parameters.

Molly fish need a clean water environment as well as healthy food to reproduce successfully. So, create a healthy and clean environment for Molly fish for breeding.

Provide Ideal Breeding Conditions

Molly fish will breed only in the right conditions. If you provide them water temperature of around 25-28 degrees Celsius, they can reproduce successfully without any problem. Also, caring about the light condition is necessary as Molly gets excited by bright light.

Maintain A Healthy Diet

Molly fish are less picky than other fishes when it comes to diet, but maintaining a healthy one is necessary for breeding them successfully. You can feed Molly’s with brine shrimp which will be their primary food during the breeding cycle, and you should also include bloodworm or daphnia in your Molly’s diet.

Do not forget to include the following most important tips in the Molly fish breeding cycle:

  • Molly needs plants for spawning, so providing them ideal conditions will help them reproduce successfully.
  • When it comes to mating, Molly’s prefer slow water with some floating plants and bright light condition which can attract Molly’s.
  • Once Molly fish reproduce, you should separate the parental couple from other Molly’s in your tank to prevent their spawning again.

Some FAQs

How Long Will It Take Molly Fish To Complete Breeding Cycle?

It takes Molly fish around 21-28 days to complete the breeding cycle. However, this depends on many factors, including water temperature and the food quality you feed them. A healthy molly fish will breed faster than an unhealthy one who spends most of its time trying to fight off diseases or parasites.

Although Molly Fish can lay up to 100 eggs at once, this is very unlikely. Molly Fish usually only lays around 100 to 300 eggs per breeding cycle.

What Is The Ideal Temperature For Molly Fish Breeding Cycle?

The best water temperature for the Molly fish breeding cycle is between 70 – 75°F (21- 24 °C). Female molly fish will die if you expose them to water temperature below 66°F (19 °C). Molly fish can survive in much colder temperatures, but egg development will be significantly slower.

What Is The Ideal pH Level For Molly Fish?

The pH level of the Molly fish breeding tank should fall under the range of 7.5-8.5. Molly fish cannot live at a pH level of less than 6.6 or higher than 8.9. Molly fish, on exposure to water with high acidic content, start burning and die in just a few minutes if not treated properly

What Type Of Food Should Molly Fish Eat To Breed?

Molly fish breeding is successful if you feed them properly. Best type of food for Molly fish breeding is a live food. It can be bloodworms, mosquito larvae, or brine shrimp, but it’s best to use a combination of different types of foods as Molly fish breeders need variety in their diet. Molly fish breeders should feed them at least three times a day.

What Is The Best Tank For Molly Fish Breeding Cycle?

Ideally, Molly’s breeding tank should have around 20 gallons of water volume and plenty of space to move around in so female Molly can swim freely while looking for the right place to build her bubble nest. In addition, Molly’s breeding tank should have a tight lid because Molly Fish are excellent jumpers.


In conclusion, Molly fish is a beautiful species of fish. They do not require an extensive tank to live in. They are easy to care for and can be very rewarding when breeding them.

This guide has taught you that the Molly fish breeding cycle isn’t that difficult once you know what you’re doing. They don’t need any special equipment or food – just water, good food, and love. Molly fish are a unique species of fish to have in your home. They’re beautiful, fun to watch, and can be enriching when breeding them.

Thank you for giving your time to read this Molly fish breeding guide. Molly-Fish offers a wide range of aquarium supplies, including filter cartridges and heaters, to ensure your Molly fish are always in the best condition possible!