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How Long Are Mollies Pregnant For? 12 Things To Know

Mollies are tropical fish and are generally pregnant for around 60 to 70 days. Female molly will give birth to 10 to 60 young as soon as the gestation period is complete. Mollies do not lay eggs. The fish hatch their babies internally and delivers the babies.

Do Molly Fish Need A Filter

What is the Molly Fish Gestation Period?

Mollies breed has a unique gestation period. The internal fertilization process is developed to hatch the eggs inside the body. Molly is not a livebearer species. They produce healthy molly fry from eggs once their gestation period is over. The eggs in the body get fertilized by the sperm.

molly fry swims out of the Mollies when they are ready, and they start swimming in the water. The gestation period of a healthy molly fish is around 60 days. Surprisingly, the female molly can store the sperm internally for a long time and get pregnant without having the male partner around. Therefore, many aquarium owners choose to have molly fish in the tank as they produce healthy molly fry without needing a partner. If you have bought a molly fish from an aquarium, they might have sperm internally that may produce the babies in the future.

So do not be shocked if you find your Molly fish producing babies as single fish in the tank. Generally, the Molly fish takes 30 days to show the sign of pregnancy. It is one of the fish breeds that give birth to the fry throughout the year.

How long does it take for a molly to give birth?

Molly fish give birth to fry about every 28 days. It can take them up to 24 hours to 3 days to give birth to all their molly fries. You will find a gravity spot ( black patch) in the belly area. And she’s going to get big and look distinct with a large belly. The first few batches of babies are all less visible, so the more batches she gets, the more noticeable they become, because every time she’ll get more fries. Before 1-12 hours, before she starts birthing fry, She may poop white.

Once they are finished they will poop normally again and will start eating their own fry if not separated.

Mollies and platies are just like guppies, they can store sperm and have up to 5 batches of fry even if they were only impregnated once.

How to Tell When a Female Molly Fish is Pregnant?

Birth signs of Molly fish would be an easy process to detect. Molly fish gain weight when they are pregnant. You can see their lower body getting bigger.

If you have the Molly fish in different colors other than black color, you will see the lower part of the body will generate a dark black spot. The black spot shows babies are getting ready to deliver. Since female Molly stores the sperm inside, most molly fish found in the stores have already been pregnant.

You will observe the mollies start giving birth to the babies as soon as their 60 gestation period has reached.

How do you know if the fish is pregnant?

1) most typical sign of pregnant molly is a swollen stomach. The female molly would start looking big when they are pregnant. The size of the stomach would grow rapidly, giving an unusual shape to the Mollie.

2) Pregnant molly would start behaviors unnatural when they are pregnant. They would look for warm water near the heater.

3) Slow triangular shape dark sport will appear near the anal vent of the pregnant molly.

4) Fish would slow down the eating habits. She will avoid the food sometimes. Less eating is a sign that the fish is having babies in the stomach.

5) As the belly of Mollie grows, you can spot the fry eyes shining in the light near the anal vents. The stomach will stretch out when babies are moving inside.

How to manage Molly’s Breeding Period Diet plan?

When to confirm that the Molly fish pregnancy signs and is getting ready to give birth to the babies, you have to prepare with Molly’s breeding period diet plan.

The right amount of nutritional food would provide the required energy to Molly fish and growing babies inside the womb. It is essential to provide the required food that would help mollies in sustainable growth. During the gestation period, mollies would reduce food consumption. Do not worry if you see your Molly is not eating in the pregnancy period. It is a normal behavior of the fish during the gestation period. It would be best if you changed the feeding pattern during the pregnancy.

Instead of feeding them twice a day, you should break the food into three to four hours of the slot and give the food to your fish 5 to 6 times a day.

Feeding mollies in the small portion would give them time to digest the food.

As in the pregnancy period, due to the babies in the womb, mollies would not have sufficient capacity to consume food and store it in the stomach. They would need food throughout the day.

Read more Is Molly Guppy Hybrid Possible? All You Need to Know

High protein food for female mollies

During the pregnancy period, the female fish would look for a richer diet plan in average fish food. High protein in the diet would help the babies to grow faster. Also, it supports Mollies to stay in good health. Lipids and proteins are the main ingredients of fish growth. It promotes the development of the embryo.

Especially in the early larval stage, mollies need more nutritional food. The Lipid and Proteins are stored in the body helps the fish to produce the yolk. The embryos are fed on the yolk, helping them to stay healthy. Using the most food and dry pallets of fish food would be an excellent option for Molly’s babies.

If you provide the pellets to the fish, go with the fish food containing the poly-unsaturated fatty acid-based food. make sure you provide mollies with enough nutrients. Nutrition is essential for the development of larvae. It is vital to give Mollies the right amount of diet.

mollies that do not get the required nutrition to utilize the Perivisceral fat from the body, which helps them develop the fatty acids for yolk production. The less nutritious food would make Molly use the body fluid to develop yolk. It may harm the mother’s health; therefore, you should take Molly’s special care during the pregnancy period. Also, the low nutritional food results in poor quality eggs. It reduces larval viabilities. you can feed them with flake food.

How to Care for Newborn Mollies?

Fish turn carnivorous after they give birth to their babies. Female Mollies do not care for their young babies. Once the babies are out of the womb of the mother, they are on their own. Keep an eye on the breeding period closely.

When Molly is about the deliver the babies, you should keep the other tank ready to move the young babies. Separate them from the mothers before the mother starts eating them. The tank where the mother molly is kept uses the aquarium plants, rocks, etc., to create a proper hiding place for the young babies.

When Molly gives birth to the babies, the babies would require a hiding place. Babies would take some time to get ready for the swim. Once the babies are ready, they will swim around and start looking for food as they will be hungry. you can feed baby mollies with baby brine shrimp.

Here are some of the ways you can prepare for the breeding space for Molly.

Separate Breeder Box:

Aquariums will have a small size transparent breeder box that would easily get fixed inside of the fish tank. It is also known as the breeder net. The place is used to quarantine the pregnant female for a while without moving it separately.

The transparent box would reside in the corner of the fish tank. Other fish will also be there in the tank, So Molly will not feel alone. You should move the Mollies in the breeding box when giving birth to the babies. Molly will start delivering the babies in the small chamber where the babies can comfortably hide and stay for a while until their mother delivers all the babies.

The box protects the babies from getting eaten by the other fish in the tank or by the mother fish. Once all the babies are delivered, separate the Molly from the breeder box and let the babies thrive in the fish tank.

The Nursery Tank:

A nursery tank would give sufficient space for the babies to thrive in the tank. Please keep all the babies in the Nursery tank so you can manage their diet plan. Feed them protein-rich food that supports faster growth. Build the Nursery tank that helps raise healthy and strong molly adult fish.

The nursery tank would have six to ten-gallon water inside the tank. It will have aquarium plants, rocks, and many other vital decorations that make the Molly fries enjoy the aquarium.

Filter unit:

Note that the small molies would produce a good amount of waste containers. The proper filtration process is needed to remove the wastewater from the tank. otherwise, water change is necessary every other day to remove the waste.

If there is no filter in the tank, the water will become foul, and it will develop health problems in the babies. Also, the decaying plant organic matter will float in the water. The contaminated water would be hard to breathe. The small particles of the plant would float around the water.

If the wastewater doesn’t get removed from the fish tank using a filter, it will toxicate the water and poison the fry. Filter that uses the foam base filtration would be good for cleaning the water. The foam will trap the small particles and suck them up while passing the tank water giving clean water.

Aquarium heater:

molly fish prefer temperatures in the range of 75°-80°F (24°-26.7°C). If your water temperature is not in the preferred range, it is better to use an aquarium heater.

Air pump:

An air pump is not a piece of the necessary equipment in the molly tank. if there are other tank mates, an air pump is not a bad idea.

Read more Complete Guide of Dalmatian Molly Care | Care Sheet


Molly female giving birth-signs is the time you should be ready for the baby mollies. Get the right equipment in the tank, prepare a separate tank for the babies, and arrange the food. As caretaker of the fish, you should be alert when Molly is pregnant. Take more care of the females during the pregnancy. Food plays an important role in the growth of babies, so use the right amount of food to feed the molly.

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About Dr.Chamika

Hello, I'm Dr. Chamika. I am a Researcher in Water quality, Aquatic organisms, and Environmental chemistry. I am a passionate fish keeper, with10 years of experience. My mission is to help other aquarists experience the joy of fish keeping.