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is my guppy pregnant?

How Can I Tell if a Guppy is Pregnant?

Guppies are known for their fascinating ability to reproduce. They aren’t called Millionfish for nothing you know!

Guppies are some of the few fish species that carry the eggs internally and give birth to fry. This makes guppies even more interesting. So, how can you tell if you have a pregnant guppy?

A pregnant guppy’s gravid spot will become bigger and darker as the pregnancy progresses. Her abdomen will also increase in size and develop a boxy shape towards the end of her pregnancy. In addition, her eating habits may change, and she will become aggressive towards other fish before birth.

Guppies are only pregnant for 25 to 30 days, giving you little time to prepare for your new arrivals. To help you prepare for your first batch of baby guppies, we will discuss how to tell if a guppy is pregnant, what to do when a guppy is pregnant, and what to do before and after she gives birth to the fry.

How Can You Tell If A Guppy Is Pregnant?

If you are a new guppy owner, you might be excited and nervous about the first guppy pregnancy. Suppose your guppies are in a suitable environment free from stressors, such as predator fish. In that case, you will have fry within two months of having your guppies.

Guppies are ovoviviparous, meaning that the female guppy keeps the eggs in her body as they develop. She then gives birth to the fry when they have already hatched. Another interesting thing about female guppies is that they can store sperm in their bodies for up to a year.

Therefore, if their tank conditions aren’t ideal for fry, they can delay the pregnancy for a later time. Then they won’t require a male’s contribution to have fry. Female guppies usually have between 20 and 60 fry per batch, and the gestational period is between 25 and 30 days. A female guppy can produce as many as 1500 fry in her lifetime.

All this is to say that you will most likely have fry at one stage or another. In fact, you’ll likely have fry quite often, which you can then sell or gift when they are mature. As this is the case, you must know how to determine if a guppy is pregnant and what to do when you discover she is.

There are a few signs that a guppy is pregnant. The first sign is the growing gravid spot on her abdomen. Female guppies have a small black spot on their abdomens where the fry will develop if they’re pregnant. During pregnancy, the gravid spot will grow bigger and become darker. The spot will continue growing until the guppy gives birth, when it will be at its biggest.

Another sign that your guppy is pregnant is a growing abdomen. The guppy’s abdomen will get bigger and bigger as the fry develop. Before she gives birth, a guppy’s abdomen will have a more boxed shape and look like she is bloated or fat.

pregnant guppy fish
A pregnant guppy

The next indicator that a guppy is pregnant is her eating habits. She will likely eat more food at first. Then, as her abdomen grows, there isn’t enough space for a lot of food, and she will start eating less.

Finally, a guppy might become hostile towards other guppies, especially male guppies, if she is pregnant. She’ll attack them if they try to mate with her. This, too, increases as her pregnancy progresses, and she will be the most aggressive before giving birth.

These are the signs that your guppy is pregnant, which is bound to happen if she is in a safe and thriving environment and there are male guppies in the tank. So, what do you do if you notice your guppy is pregnant?

What Should You Do If A Guppy Is Pregnant?

You may feel very excited when you first realize your guppy is pregnant. Watching a guppy’s pregnancy and birth is a fascinating experience for any guppy owner. So what can you do to prepare for the birth of your guppy’s fry?

There isn’t much to do when the guppy is pregnant. If your fish tank doesn’t have an isolation tank, we recommend buying one before the guppy gives birth. The isolation tank will help the guppy relax while she gives birth and prevents the fry from being eaten by the other fish.

Some isolation tanks have a separate compartment for the fry, like this one. These tanks are ideal for guppies, as the fry has a safe space to mature where the mother and other guppies can’t eat them. Guppies will try to eat their fry, so separating them is crucial if you want them to live. You can read more about this here.

Another thing you can do when your guppy is pregnant is to feed her a variety of food. Include fish food flakes, fresh brine shrimp, frozen blood worms, and spirulina flakes. These foods will help the fry develop and ensure the mother is well-nourished during the pregnancy.

As her pregnancy progresses, the guppy won’t be able to eat as much food at once anymore. Therefore, we recommend feeding her smaller meals throughout the day to keep her well fed and ensure there isn’t too much food waste in the tank.

Your guppy will be ready to give birth to her fry within a month! So what should you do when your guppy is going into labor?

pregnant blue guppy
Not long to go…

What To Do When A Guppy Gives Birth.

You can tell that a guppy is close to giving birth by the shape of her abdomen. You know that labor is close when it develops a more boxed shape. The gravid spot will also be huge and dark when she is close to giving birth.

Additionally, your guppy may start breathing fast. She may swim up to the tank’s surface and look like she is panting when she is close to labor. She will also start nesting, which means that she will find one corner in the tank and stay there, attacking any other guppies that come close.

A guppy will also have contractions. You can see these contractions by the way she moves. Her back will be straight, and her tail will point upwards when she has a contraction. When you notice these signs, you should prepare for the fry.

Gently move the guppy from the main tank to the breeder tank, where she can peacefully give birth to her fry. If she hasn’t delivered any fry within 48 hours after moving her, place her back in the main tank and slightly raise the temperature.

However, if you move her to the breeder tank when she is about to deliver, you can watch as the baby fry are born. Some eggs may be undeveloped, and some fry may not survive. However, there should be between 20 and 60 new fry in the isolation tank if all goes well. A guppy takes between 2 and 6 hours to deliver all the fry. In some cases, it can also take up to twelve hours.

This short video shows you signs to indicate your guppy is about to give birth.

How To Care For A Guppy And Fry After Birth.

If you have a separate section in the breeder tank for the fry, leave them there for a few days to mature. Also, leave the mother in her isolation tank for 24 – 48 hours after delivery so she has time to rest and recover. Then, feed the mother nutrient-dense food so she can regain her strength. After that, place her back in the main tank.

Feed the fry often so they can grow big and strong. Experts recommend feeding them up to 5 times per day. The fry must be big enough, so the adults won’t eat them before moving them to the main tank. This can take a few weeks. Determine the sex of the fry before moving them and sell or gift the fry you don’t have space for.


Guppies have a gestational period of 25 to 30 days, giving you little time to prepare for their arrival. A pregnant guppy’s gravid spot grows bigger and darkens. Her abdomen swells and develops a more boxed shape. Her eating patterns change, and she can also become more irritable. If you notice these signs, there’s a good chance you will be welcoming fry into your tank within a month.

Further Articles about Guppies:

Are guppies fin nippers?

Will guppies eat snails?

Why is my guppy not eating?

How to stop a bullying guppy.

Do guppies eat plants?

Do guppies like current in their tank?

How long do guppies live for?

Can guppies be aggressive?

Why does my guppy stay at the bottom of the tank?

Can guppies change colour?

How high can a guppy jump?

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