How Long are Molly Fish Pregnant?

Molly fish are great to start with if you want to keep your aquarium clean and easy to care for, with little maintenance required. But when it comes to reproduction, there can be some confusion when determining how long molly fish are pregnant and what the stages of pregnancy in molly fish look like.

The length of a molly fish’s pregnancy varies depending on the species, but generally, it lasts between 40 and 60 days.

This article will explain how long molly fish is pregnant and what signs of pregnancy in molly fish, you can expect.

How Long do Molly Fish Stay Pregnant? 

The Amazon Molly is a childbearing fish and will carry her fry for between 50-60 days. They have already formed into fry before they were laid, so it doesn’t matter how many eggs your female has produced, all of them will turn into fully developed baby fish.

Because of their short gestation period, you should be able to see signs of pregnancy in around three weeks from when your female was first introduced to your male.

Signs include larger flatter bellies and large bumps appearing on either side of their head where their brood pouches form. These pouches become visible once they have been filled with developing fry.

How Long Do Molly Fish Stay Pregnant

During pregnancy, most females will stop eating altogether until after she has given birth to their young, at which point they will eat as much as they can in order to replenish any lost nutrients during gestation. It is important that you don’t overfeed your female though or else she may become ill due to an overload of toxins within her body caused by too much uneaten food decaying inside of her stomach.

If you notice that your female is eating less than usual or not at all then try feeding some live foods such as bloodworms and brine shrimp while reducing the amount of dry food that she receives until she starts eating normally again.

What are the Signs of Pregnancy in Molly Fish?

A Swollen Belly

Just like humans, a large belly is the most obvious and easiest symptom of a pregnant Molly. Furthermore, the eyes of the fry can also be seen as a blackish patch or line running down her stomach. As the pregnancy proceeds, the pregnant molly’s body will continue to plump out and round out.

A Swollen Belly molly fish

However, because mollies do not acquire a big belly right after fertilization, this symptom is usually only relevant in the latter few weeks of pregnancy. Furthermore, on darker-colored mollies, the black mark isn’t apparent, so keep an eye on their abdomen.

Behavioral Changes

Fortunately for fish owners, pregnant Molly’s behavior makes identifying a pregnancy among the species easier.

When the fish conceives, you’ll notice that your normally calm and well-behaved Molly becomes more aggressive.

molly fish Behavior Changes

This does not, however, imply that your female Molly will fight others without cause. A pregnant Molly, on the other hand, will be irritated by any other fish that disturbs her relaxation in any way. That’s why, during their pregnancy, pregnant Mollies prefer to spend the majority of their time in convenient hiding areas.

Changing Appetite

To meet her increased nutritional needs, molly’s appetite begins to increase after conception. You’ll notice she becomes more energetic during feeding time and may even fight other fish for food, so make sure there’s enough food for everyone.

Molly’s appetite will begin to decline as the laboring stage approaches, and she will spend more time alone. Though it can be tough to determine when a molly is eating more or less, you will notice a shift in their hunger if you keep a close eye on them.

A Gravid Patch

A gravid patch can be found near the anal fin of pregnant fish species. During the fish’s gestation stage, this patch usually develops in size and changes color.

A molly Gravid Patch

Similarly, if the gravid area around the lower body of your Molly fish darkens in color, you can be sure it’s pregnant. It’s straightforward to figure out what causes the spot to change color. Because Molly fish have translucent skin, the Gravid patch allows you to view what’s going on inside their bodies.

How to Care for Molly Fries?

Molly newborns are not shielded by their parents. The small fish are just as likely to be eaten by their own mother as they are by other aquarium fish, so they’ll need some support to live.

Large Tank Size

They require ample tank space, live plants, and aquarium equipment to balance the tank environment. You can get a tank size ranging from 10 to 20 gallons. While these requirements are met, tank size is critical for the Molly fry to develop and thrive.

Do not add Aggressive Tank Mates

Not to mention, Mollies give birth to a large number of Molly fries all at once. As a result, the number of births could approach 100. As a result, the tank must be large enough to accommodate a huge number of Molly fry while also providing a pleasant environment. Despite the fact that you will be raising little Molly fry, a substantial tank size of 10 to 20 gallons is required for them.

Prevention from Diseases

Because many bacteria in the air inflict harm to other living things, they want to get into the water, or you could argue that some parasites or fungi that appear to be microbes are always present in water. Our ultimate goal is to save and grow our fish babies to adulthood.

Constant Water Temperature

Mollies are usually tropical fish. As a result, getting a warm temperature in their tank is critical even for Molly fry. Maintain a water temperature of 72 to 84 degrees Fahrenheit for molly fish fry (23 to 28 degrees Celsius). Molly Fry’s metabolism will be boosted by the warm water, allowing her to eat properly and grow properly.

Optimal Water Temperature for Fish Tank

To maintain the water temperature regular and accurate, I recommend investing in an aquarium heater. Additionally, you can use an aquarium thermometer to determine the current water temperature in the tank.


Artificial and living plants can be used to adorn the aquarium. The important thing to remember is to fill the tank with plants before adding Molly fry. Keep in mind that your molly fish, as well as their young, dislike being in an aquarium with a lot of aquarium plants like Java Moss, Java Fern, and grasses. It’s the ideal hiding spot for your Molly fry.

Clean the Plastic Plants

You can also add some floating plants, which are good for babies since they give them a place to hide near the surface just after birth.

The Bottom Line on How Long are Molly Fish Pregnant?

Mollies are generally pregnant for 2-3 months before giving birth and they give birth to hundreds of fry. These Fry are abandoned by their parents and they might even eat them! So it is up to you to save your guppies.

Molly fry care includes everything from isolating them from the main tank to properly raising them in a separate tank. Feeding them a nutritious diet and protecting them from fish disease are also important considerations while caring for them.

However, after you understand all about Molly’s fry care, you won’t have to be concerned about them!

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