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Does Molly Fish Give Birth All At Once? ( Surprising Answer )

Mollies are popular among many aquarists because of their vivid colors and their peaceful nature. Does Molly Fish Give Birth All At Once? Once a female molly is pregnant, and if she doesn’t have any physical issues or stress, she will give birth to all fish babies at once.

Molly fish are prolific breeders that give birth to babies all year along. So, you should be prepared to welcome more mollies if you have some. So, it is not surprising to see several fish fries at once in your tank. But this birthing process takes time.

This article will talk about how female mollies become pregnant and how long it takes them to give birth.

And also, if you are a newbie and don’t know whether there is a need to worry about mollies multiplying fast, we will also provide some tips on how to deal with a large number of fish fry.

Does Molly Fish Give Birth All At Once

Do mollies breed easily?

Yes. Mollies are livebearer fish that give birth to fish fry.

These fish get pregnant very easily, and they will spawn within a few weeks after they are born. Mollies require very little time to get pregnant, and they can give reproduce at any time if there is a male and female among them.

Mollies reach sexual maturity at eight weeks of their age and start reproducing soon after they mature.

Further, they don’t require conditioning or certain water conditions to breed. They will breed as long as there is a male and a female fish in the tank. Additionally, once spawned, female mollies can store sperms for future use.

How many babies do mollies have?

Typically, a female molly will give birth to 40-100 live baby fish at once.

But this number varies from molly species to species and the size of the fish. Some molly species give birth to 5-13 babies at once, while others may have as many as 100 babies at once.

The number also varies with the age of the mother fish and other factors that affect her health during pregnancy.

How often do mollies have babies?

The gestation period of mollies is around eight weeks.

After about 60 days, the female molly gives birth to live baby fish. However, if the female fish already have sperms stored, she may give birth to fish fry as often as every 30 days.

At what age do mollies start breeding?

Mollies become sexually mature when they reach eight weeks old.

This is when they can reproduce and start giving birth to baby fish. However, some species become mature at six weeks of age.  

Does molly fish give birth all at once?

As we mentioned before, once the fish are fertilized, molly fish will keep all of them in her belly until they hatch and will give birth to all the live fish fry at once.

This doesn’t mean that she just injects all the fish babies at once. Mollies give birth to babies one by one, and it takes some time.

How long do mollies take to give birth?

Molly fish takes approximately one day to finish giving birth to new babies.

She gives birth to one fish at a time, and in between, she rests. So, in reality, it takes around 24 hours for her to give birth to all fry.

Molly pregnancy stages

Molly fish pregnancy starts when the female molly produces the eggs.

This will happen when the fish reach sexual maturity, and it takes only days for the female molly to produce eggs. Then she will spawn with an available male and fertilize her eggs in her abdomen.

Unlike egg-laying fish, mollies do not release eggs while spawning—they intercourse and store sperms for future use. The gestation period of mollies is around eight weeks.

After about 60 days, the female molly gives birth to live baby fish that look like adult fishes from their appearance.

If the female molly has laid eggs, it means that she has had a miscarriage or an abortion. If molly has laid eggs, the eggs will not hatch.

The behavior of molly about to give birth

When your molly fish is about to give birth, her behavior changes along with her physical appearance.

When it is near to give birth, the female molly will develop a bulge below the gills. Her belly becomes broader and more profound and will look more square at the downside. Her gravid spot enlarges and will be darker.

The pregnant molly swims less than before and prefers to stay in one spot for a long time. Often, she will hide behind plants to make it hard for the other fish to come near the tank.

Female molly will stay in a dark area if not covered when giving birth. However, this is not the final giving birth spot since she will move to the new place after taking a rest.

How to care for the molly fish fry?

Molly fish fry care begins before the pregnant molly gives birth as adult fish can and will eat fish fry once they are born.

You will have to move the pregnant molly fish to a breeder tank for the birth to take place and raise the fish fry in another tank.

The breeder tank should be clean and contain plenty of plants for the female molly to take cover. After the birth, move the mother fish back to the main tank. Otherwise, she will eat her fish fry.

You should keep a sponge filter in the breeder tank to filter the waste. The fry will be too small to eat flake food, so you have to feed them with baby brine shrimp.

You can also provide them with powdered fry food. Be careful not to overfeed the molly fish fry as they will get sick if overfed.

Once the fish are large enough to survive on their own, you can move them back to the main tank. This will take only 2 to 3 weeks as they grow fast.

Do mollies eat their babies?

Yes. In the wild, mollies eat eggs and fry as these are their natural prey.

They may eat their own fish eggs or fry in a fish tank. If they are big enough to eat them, the mollies may also eat their babies as they are cannibals.

You will have to separate the mollies and the baby fish in different tanks for this reason.

What to do with molly fries?

If your tank is small, you may not be able to keep all of your fish fries at home. So, you can donate some of them to a local aquarium or a pet store.

In most cases, the pet stores have a special section where you can donate your fish fry. They will take care of them and raise them to be sold in the store as pets or for breeding.

You can also sell them if you can find a buyer. As these fish are super cheap, they are easy to sell.

If you prefer, you can give your fish away for free in a community Facebook group or on Craigslist.

If any of the above steps don’t work, and you want to get rid of them, you will have to cull them as releasing them into the wild is not wise.

Please do NOT release the molly fish fry into your local pond or water stream, as introducing these species might threaten the natural population.


The average time for a molly fish to give birth is around 24 hours, but it could be shorter or longer depending on the individual fish.

If you are impatient and want to see your fry swimming around in your tank, just be patient and wait. You will likely have a happy surprise one day when you come home from work, and all of the fries will be there!

Credit to : Aqua Maniacs
Read Next : What Do Molly Fish Eggs Look Like ? (Are They Real?)

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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.