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How To Know If Your Molly Fish About To Give Birth?

Molly fish are a popular choice for beginner and seasoned fish keepers because they are easy to care for and fun to watch in an aquarium.

If you are a molly fish owner, you may be wondering how to know if a molly is about to give birth. Well, don’t worry; we’ve got it covered.

This article will discuss how you can predict when the molly fish will give birth. By understanding the signs and preparing in advance, you can give your molly the best environment to give birth and her fry the best possible chance of survival.

So without further ado, let’s dive in!

How Can You Tell If A Molly Is About To Give Birth?

how to know if your molly fish about to give birth
Typically, to know if a molly is about to give birth, you should look for some sign. These include physical changes, such as a change in the shape and size of the belly and darkening of the gravid spot, as well as behavioral changes, such as less swimming, more hiding, lack of appetite, etc.

If your molly fish is showing any or all of the above signs except a big squared-off belly, then there might be something wrong with your fish, and it is not pregnant and will not give birth.

The main thing that will be there when a molly is going to give birth is a prominent rounded belly! It’s inevitable, so you should look at it before anything else.

If you don’t pay attention to these signs and are not prepared for the birthing stage, you will be surprised or even shocked once molly gives birth.

As the fries are tiny other fishes in the community tank, including the mollies themselves, think of them as food and usually eat them.

Hence it is essential to know about the changes a fish goes through before it gives birth so you can save the fries.

Now let’s look at the signs in detail:

1. Change in Shape and Size of Belly

One of the most prominent signs that a molly fish shows when it is about to give birth is a change in the shape of its belly.

It is especially noticeable if you are used to seeing your molly’s normally thin and streamlined body shape.

As the fries (baby mollies) grow inside the female, her womb will stretch, get bigger, thicker, and be more squared off.

how to know if your molly fish about to give birth

                                     Round Belly

Right before she is ready to give birth, she’ll have a very squared-off belly, so much so that you might think it will explode.

It is a good indication that the molly is getting closer to giving birth, possibly in the next 7 to 10 days. By paying attention to the changes in your molly’s belly, you can be prepared for the birth of her fries.

2. Opaque Gravid Spot

The gravid spot is a dark triangular area near the anal fin that becomes bigger and even darker as the molly fish gets closer to birth or the fries (baby mollies) grow inside her.

It becomes more opaque as the fish gets closer to giving birth, and in the final stages of pregnancy, you can even see the eyes of the fries through the gravid spot.

When you notice it, be prepared for the arrival of tiny fries in a few coming days.

3. Behavioral Changes

Similar to the physical changes, some behavioral changes may indicate that your molly will soon drop the fries.

Behavioral changes that may occur in mollies are:

Swimming less: As mollies get closer to giving birth, they may swim less or become less active and instead prefer to stay in one place in insolation. It is an instinct as they need a peaceful environment when giving birth. Moreover, they don’t want to be bothered by any other fish.

Hiding behind plants: Mollies may also seek out hiding places, such as plants or other objects in the tank, as they get closer to giving birth. It is another instinctive behavior, so feel safer and don’t get stressed.

Apart from these, the molly fish is aggressive toward other fish.

4. Loss of Appetite

A pregnant molly generally eats more as she needs the energy to develop fry; however, as the birthing stage comes near, you will notice that her appetite will decrease.

The fish will not show any interest in eating and will hold back when you offer them something to eat. When it happens, you should not worry; it simply means that the time for molly fry’s birth is near.

What To Do When Your Molly Fish Is About To Give Birth?

how to know if your molly fish about to give birth
It is generally a good idea to separate the molly mother from the other fish when it’s going to give birth; it can help reduce stress and keep the molly safe from other fish.

If you decide to separate the pregnant molly, you should set up a separate tank for her with water and decorations taken from the main tank.

Make sure the separate tank is large enough for the mother to release the fries and has plenty of hiding places. Doing so will help her feel more comfortable and familiar with her new surroundings.

Also, after birth, it is crucial to place the molly back again in the main tank and keep the fry separate from the adult fish for at least 2 weeks or until they are large enough to be introduced to the main tank. It is because the fries are very small and vulnerable, and larger fish can easily eat them.

Last but not least, ensure the water temperature in the new tank is around 72-78 degrees Fahrenheit, has hideouts for fries, and a filter with foam or sponge to over the intake on the filter, so the fries don’t get sucked into it.


So that’s it for today’s article. We hope after reading this article, you can now know if a molly is about to give birth.

In a nutshell, if you pay close attention to both physical and behavioral changes in molly, you can tell when she’ll deliver the fries and can take all the necessary steps in advance to ensure a safe and smooth birth.