Pregnant Guppy 101: Signs, Behavior, Stages, Care & More

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A pregnant guppy fish comes with a lot of questions. That is especially true if it’s your first time in this situation. This guide will take you step-by-step through the process of growing a pregnant guppy fish. I will try to cover all the different aspects of this topic.

For example, you’ll learn how to identify a pregnant guppy fish, how long it remains pregnant, and the general pregnancy stages. I will also teach you how to care for pregnant guppies to ensure they eventually give birth to healthy fry.

So, without further ado, let’s dive into it.

Also Read: Guppy Care Guide

How To Tell If A Guppy Is Pregnant?

These signs indicate that a guppy fish is pregnant: 

  • The belly grows larger each day. 
  • The gravid becomes darker. 
  • The guppy hides behind plants and decorations. 
  • The guppy presents aggressive tendencies. 
  • Pregnant guppies lose their appetite. 
  • You will see the fry eyes at the lower part of the abdomen. 
  • The guppy will turn white. 
  • Your guppy will choose to swim at the top.

Pregnant guppies typically present a few of the signs mentioned above. Bear in mind that constipated guppies will also grow larger. However, if you’re looking at a female, it is most likely pregnant.

Still curious? Click here for more information on how to tell if a guppy fish is pregnant. I also included a helpful video that illustrates the behavior and appearance of pregnant guppies.

How Long Is A Guppy Pregnant?

Guppies are usually pregnant for 21 to 31 days. Typically, they are pregnant for shorter periods if the aquarium conditions are adequate. That includes the temperature, pH, and hardness. Some guppies will give birth faster due to high temperatures, but the fry might be deformed.

After a month, your pregnant guppy is likely to deliver its fry. If you notice that the belly is already swollen, you can assume that ten to eighteen days have passed. Therefore, the fish will be ready to give birth in about two to three weeks.

Still curious? Click here for more information on how long guppy fish are pregnant. I also discussed how fast guppies can get pregnant again after giving birth and how you can make guppies give birth faster.

What Are The Guppy Pregnancy Stages?

These are the pregnancy stages of a guppy fish:

  • Days 1-7: A bright gravid spot with a flat belly.
  • Days 7-10: A darkening gravid spot with a slightly swollen belly.
  • Days 10-18: A deep dark gravid spot with a round belly.
  • Days 18-25: A distended, square-shaped belly.
  • Days 25-31: The fry eyes are visible through the abdomen.

Here are some pictures that will help you decide at what stage of pregnancy your guppy fish is. Follow these to get a better understanding of when your guppy will give birth:

This guppy is in the early days of pregnancy (about 1 to 7). The gravid spot is pretty bright, and the belly is still flat.
This guppy approaches the 10th day of pregnancy. You can see that the gravid spot turned darker. Also, the belly is a bit swollen.
This guppy has been pregnant for 10 to 18 days. The gravid spot is deep-dark, and the belly is rounded.
Here is a guppy that has been pregnant for 18 to 25 days. The belly took on a square shape. It also seems pretty distended.
This guppy has been pregnant for 25 to 31 days. During the final days of pregnancy, you can easily see the fry eyes.

Still curious? Click here for more information on the guppy pregnancy stages. Besides the gestation period, I discussed what happens before and after your guppy gives birth. I also included a video showing a guppy during the delivery process.

How Do You Know When A Guppy Is Going To Give Birth?

These signs suggest that a guppy is going to give birth: 

  • There are contractions across the guppy’s body.
  • The guppy’s belly looks boxy.
  • The guppy will hide a lot and breathe heavily.
  • The gravid spot is deep-dark.
  • The fry eyes are seen on the lower abdomen. 
  • The guppy will lose its appetite. 
  • Your guppy will lash out at its tankmates. 

Try not to make drastic changes if your guppy approaches its due date. At this point, your fish is highly vulnerable. Additional stress might harm the fish and possibly kill it. Placing a divider to prevent the mother from eating the fry might be the only wise thing to do.

Still curious? Click here for more information on how to tell when a guppy is about to give birth. In this article, I embedded an excellent video that shows how guppies approaching labor behave.

Should I Separate Pregnant Guppies?

Generally, it is better to separate pregnant guppies. That prevents the tankmates from harassing the vulnerable guppy, potentially causing a miscarriage. Yet, the tankmates should be separated from the pregnant guppy, not the other way around. Moving the mother during pregnancy can be harmful.

If you suspect that your guppy is pregnant, take away the tankmates while leaving the mother in the original tank. Then, place a divider with tiny holes. That will keep the mother from eating her fry.

Still curious? Click here for more information on whether you should separate pregnant guppies. In this article, I discussed the pros and cons of doing so and, ultimately, which approach you should take.

How Many Babies Do Guppies Have?

Guppies may deliver between 5 to 80 babies each time. They are fertile for about 57 months, so they can deliver between 300 to 4500 fry in a lifetime. Yet, guppies kept in a stressful environment with inappropriate water parameters will produce fewer babies.

Guppies can produce a large number of fry in each batch. However, on average, only 20 to 30 percent survive. Some of them will get eaten by the parents or other fish. That is why placing a divider is crucial.

Still curious? Click here for more information on how many babies do guppies have. In there, you’ll also learn how to adjust the water parameters for these gentle creatures. That will increase the survival rates dramatically.

Why Is My Pregnant Guppy Not Giving Birth?

Pregnant guppies may not give birth for the following reasons: 

  • Your guppy is still in the early stages of pregnancy.
  • The guppy wasn’t properly fed.
  • The water is too cold.
  • Your guppy is too stressed.
  • There are bullying tankmates in the aquarium.
  • Your pregnant guppy is sick.

If your guppy isn’t giving birth, you should first estimate its pregnancy stage. As was mentioned earlier, guppies can stay pregnant for a month, so it might just be too early. Use the guppy pregnancy stages guide above.

Then, make sure that the temperature is around 82 degrees F. This is considered optimal for pregnant guppies. If you’re not using a heater, you may consider getting one.

Still curious? Click here for more information on why your pregnant guppy is not giving birth. I made sure to discuss the interesting case in which your guppy isn’t actually pregnant. Some conditions may force your guppy to swell, even if it’s a male.

Do Pregnant Guppies Stay At The Top?

Pregnant guppies usually stay at the top when ready to give birth. That allows them to deliver their fry in a peaceful environment, with as little harassment as possible. Yet, some guppies will swim at the top when they are looking for food or potentially sick.

If your pregnant guppy is swimming at the top of the tank, it is most likely in labor. At this point, I suggest looking for additional signs suggesting that your guppy is going to give birth, as was mentioned earlier.

Still curious? Click here for more information on pregnant guppies staying at the top. There, you’ll learn what steps you should take if your pregnant guppy is consistently swimming at the upper sections.

Why Is My Pregnant Guppy Not Eating?

Pregnant guppies usually stop eating because of the stress related to the pregnancy, especially when approaching their due date. However, some guppies won’t eat because they are kept in a breeding box for too long or suffer from the wrong water conditions.

It is prevalent to see pregnant guppies stop eating. As they are highly stressed, they no longer focus on food. That becomes more prominent during the final week of pregnancy. At this point, you should continue feeding your guppy, but in smaller quantities.

Still curious? Click here for more information on why pregnant guppies stop eating. In this article, I discussed the proper timing in using a breeding box and the right approach with a guppy that isn’t eating.

Why Did My Pregnant Guppy Die?

Pregnant guppies typically die because of a complication at birth, with the most common being a fry stuck in the birth canal. However, stress can also make guppies die before or after giving birth. That can be secondary to aggressive tankmates, inadequate water conditions, and toxins.

If your pregnant guppy died, that doesn’t mean it’s your fault. Some guppies are just unlucky and die due to complications at birth. However, it is best to eliminate factors that cause stress, as giving birth is stressful enough.

Still curious? Click here for more information on why pregnant guppies die. In there, I take you step-by-step on what you should do to prevent this from happening again. I also embedded a helpful video that discusses that particular issue.

How Do You Take Care Of Pregnant Guppies?

Pregnant guppies are hard to miss because they develop prominent symptoms, including a swollen abdomen and a larger ovipositor. Pregnant guppies will also manifest aggressive tendencies.

However, once you determine that the guppy is pregnant, you must take steps to care for it. Otherwise, it may abort its offspring.

Fortunately, if you can care for healthy, non-pregnant fish, pregnant guppies won’t present a challenge. Keep the following in mind:

1. Feed Your Guppy High-Nutritional Foods

Pregnant guppies will eventually lose their appetite. Nonetheless, you are still expected to add nutritious foods to their tanks. That includes frozen brine shrimp, high-quality flakes and pellets, freeze-dried bloodworms, etc.[1]

You cannot force the guppy to eat. But you have to make sure that the tank has plenty of food just in case the expectant mother decides to eat. 

If the female shares a tank with other creatures, you don’t have to make significant changes to the quantity or quality of the guppy’s diet. But if you’ve decided to keep the pregnant female in a separate tank, reduce the size of the meals. 

Because the guppy’s appetite is fading as the pregnancy advances, you ran the risk of overwhelming the breeding aquarium with leftovers. By cutting back on the quantity of food added to the tank, you can reduce the volume of leftovers.

Leftovers are only problematic if you don’t want to increase the frequency of your cleaning regiments. But if vacuuming the tank every other day doesn’t bother you, maintain the guppy’s old feeding habits.

2. Consider Separating The Mother

Will you use a breeding box or a separate tank? Both options achieve the same objective. They protect pregnant guppies and their fry from aggressive neighbors. But breeding boxes are more stressful for fish.

You have to wait until the guppy is ready to give birth before moving it to the breeding box. The moment it gives birth, you must remove it. Breeding boxes can trigger premature labor in pregnant fish and stress that can lead to death in mothers who have given birth.

You are better off moving the fish to a separate tank. This means buying a new tank, an expense that some aquarists don’t want to incur. Additionally, separate tanks can also induce stress because the guppy has to grow accustomed to a new environment.

Admittedly, it is easier to tailor the conditions in the water to suit the pregnant fish if it lives alone in a breeding tank. However, some aquarists prefer to leave the mother in the main aquarium.

If the pregnant guppy has an abundance of hiding places, she will survive, along with her offspring. The choice you make will depend on the personalities of your guppies and the observations you’ve made. 

Some female fish are better off in breeding boxes. Others will thrive in separate tanks. You also have those that can get by in the community tank despite the presence of predators that may target their young. 

Also Read: Guppy Fish Tank Mates

3. Choose The Right Tank Size

The last thing you want is to keep a pregnant fish in a crowded environment. The stress will compromise the creature’s health, leading to abortions, death, or reabsorption.

If you have a separate tank, forget about the mother; plan for the fry instead. Once the mother gives birth, you will move her back to the main aquarium. The babies will stay in the breeding tank for the next few weeks.

Therefore, you must take the offspring into account when you consider the size. Guppy babies require a minimum of ten gallons.[2] Ten gallons can accommodate a pregnant guppy during the 30 days of its gestation period.

4. Maintain The Right Temperature

Maintain temperatures of 76 to 80 degrees F in the tank.[3] Cold water is not acceptable because it will make the fish sluggish. This is problematic because pregnant guppies are already lethargic.

Hot water, on the other hand, will cause stress. That is why I suggest keeping the temperature within the range mentioned above. It suits the mother and her babies.

Naturally, you cannot maintain the correct temperature without a heater. Make sure you get one before the guppy falls pregnant. If you have a heater, maintain it. A malfunction in the heater will cause the temperature to plummet.

5. Adjust The Water Quality

Expectant mothers are even more sensitive to poor-quality water than non-pregnant guppies. You have to prepare the breeding tank carefully before you add the female. It requires a pH of 6.8 to 7.8 and a hardness of 75 to 125 ppm.[4]

Also, make sure that toxins like ammonia, nitrates, and nitrites are kept at 0 ppm. To measure these, I personally got the API Water Test Kit (link to Amazon). This bundle is highly accurate. It also lasts for eight hundred measures, making it pretty cost-effective.

6. Maintain A Clean Environment

Perform regular water changes in the breeding tank. Do the same for the community tank if you don’t want to separate the pregnant guppy. The aquarium may accumulate more leftovers than usual because the fish loses its appetite over time.

On top of reducing the size of the meals, you should vacuum the substrate routinely. Don’t forget to remove any debris you can see. Don’t neglect the breeding tank once you move the female back to the main tank.

The babies will die if you permit their water quality to deteriorate. Change a quarter of the water each week. If you detect significant spikes in the ammonia, don’t be so quick to perform a substantial water change. Some of the fry won’t survive the process.

Instead, buy water conditioners, such as the well-known Seachem Prime (link to Amazon). They can neutralize the toxin within minutes. Water conditioners will buy you the time to perform more minor water changes until the aquarium is clean.

I also suggest adding air stones and pumps to aerate the water. This will keep oxygen deficiencies at bay. For my aquarium, I got the Hygger Aquarium Air Stone (link to Amazon). It is pretty quiet and gets the job done.

You need a filter that matches the size of the breeding tank. Because the breeding aquarium has to accommodate the babies when they are born, cover the heater’s intake valve with a sponge. Otherwise, the babies will get stuck in the filter because of their small size.

7. Adjust The Aquarium Lighting

I highly suggest giving the guppy a regular day/cycle; the fish needs 8 to 12 hours of day and night. Also, pregnant fish require heaters. They cannot rely on the ambient temperature. 

However, this is not true for the lighting. You don’t have to buy artificial lighting, especially if you have financial constraints. 

Position the tank in a room with a window.[5] Rather than creating an artificial day/night cycle, the aquarium can rely on a natural day/night cycle. Don’t subject the guppies to permanent light or darkness. The resulting stress will harm pregnant females. 

8. Scatter A Few Hiding Places

Add some plants to the aquarium. Community tanks require more plants than breeding aquariums because the pregnant guppy must hide from potentially aggressive tankmates. 

But you shouldn’t add so many plants that they overcrowd the guppy’s aquatic environment. You can also use decorations like pots, caves, and any other item that provides a decent hiding spot. 

Avoid toys that can trap the fish, especially the babies. You should also steer clear of objects with sharp edges that can damage the guppies.

9. Add More Females To The Tank

If you don’t want to separate the pregnant guppy, make sure the male guppies have plenty of females to mate with. A male guppy will not hesitate to harass a pregnant female if it wants to mate. This harassment can lead to death.

If the female survives, she may abort her offspring. If you can’t afford a breeding tank, you probably don’t have the means to buy a separate aquarium for the males. 

Rather than taking them out, add more females to occupy the male fish until the pregnant female gives birth. Each male guppy requires two to five females. 

10. Pick The Right Tankmates

If you want the pregnant female to stay in the community tank, make sure the guppy’s neighbors are friendly. Guppies can coexist with species like mollies, cory catfish, zebra danios, and cardinal tetras.[6] 

Stay away from large fish with aggressive tendencies such as Oscars and African cichlids. Even with ample hiding places, a large and violent fish will hunt the female guppy down. 

If the pregnant guppy survives these encounters, the stress could kill it, delay the pregnancy, or cause an abortion. If the guppy’s tankmates refuse to behave, move the pregnant female to a separate tank or breeding box. 

11. Make Sure Your Tank Is Cycled

Don’t keep pregnant fish in a tank you haven’t cycled to completion. They will die. Cycling introduces good bacteria that process waste.

If your tank is not cycled, the ammonia concentration will spike incessantly, and the frequent changes in the water’s chemistry will harm the guppy.

You can cycle a tank by adding fish (that introduce ammonia via their waste) or buying filter media that came from an established tank.[7]

If you throw your filter media away or wash it with chlorinated water, your tank is not fully cycled, not anymore. This is because you destroyed some of the good bacteria.

Keep this in mind the next time your pregnant fish manifests signs of distress. The cycling issue goes unnoticed because many aquarists do not realize that they can undo the results of the cycling process down the line.

Also Read: Guppy Fry Care

Pro tip: If your guppy is pregnant and will give birth soon, you’ll need to know a little more about the babies. On that matter, feel free to check my complete guide on guppy fry.


Guppies are typically pregnant for 21 to 31 days. You can expect anywhere between 5 to 80 fry when they give birth. If you identify that your guppy is pregnant, it will likely give birth with no issues. That is because guppies are easy to breed.

Focus on maintaining a stress-free environment. You may consider removing the tankmates to another tank, turning your community tank into a breeding aquarium. 

Then, introduce a few hiding spots. You can you artificial plants that won’t change the water chemistry. Then, check the water parameters, and ensure that the temperature falls between 76 and 80 degrees F.

Consider getting a conditioner if toxins like ammonia, nitrates, and nitrites are too high. Adding a few drops will cause less stress than replacing the water. But if you decide to conduct a water change, stick to 15 to 25 percent once per week.