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Beginners Guide

How To Tell If A Guppy Pregnant

by Catherine Tran 30 May 2023 0 Comments

How To Tell If A Guppy Pregnant

Guppies are common breeders who tend to spawn continuously when conditions are right. Learning to recognise pregnant guppies is not tricky. All you need to do is understand the basics of their biology.

There are many ways to know that you have pregnant guppies. If you are looking for guidance on how to care for pregnant guppies, how to tell if guppies are pregnant and how to help fish give birth to healthy babies, continue reading this article!

You catch the mating behaviour of male and female fish.

One of the easiest ways to know you have pregnant guppies is to witness the mating process first-hand.

Guppies are not afraid to breed. While other species require precise water parameters and environmental conditions, guppies are much more flexible regarding reproduction. When conditions are right, the male will initiate mating by chasing the female around the tank.

Mating is a quick process that most aquarists need to notice, and you'd often mistake it for aggression. However, once you know you are questioning whether or not your fish is pregnant, it will be easier for you to recognise that behaviour and use it as a sign of pregnancy in the weeks that your guppies are pregnant next time.


There are changes in the appearance of Gravid's spot.

The gestational position is a unique physical feature unique females. The dark skin of the womb lies just behind the anal fin. This area is usually visible in female guppies, whether pregnant or not, because of their semi-transparent belly skin. When the egg is successfully fertilised, the young begin to develop in the nest. Pregnant female guppies with darker spots.

If your guppies are pregnant, you will see a series of noticeable signs as the pregnancy progresses. The most apparent motion is pregnancy spotting, a dark spot on the fish's underside.

Guppies' gill spots will gradually darken as the guppies inside your pregnant fish get more extensive. Finally, you can even see the tiny fry's eyes peeking out!


Belly gets bigger

Like most pregnant creatures, female guppies will swell as pregnancy progresses. The change in size only happens after some time. It was a slow process that took several weeks.

Female guppies carry their young in their stomachs for a few weeks after being fertilised. When guppies become pregnant, they will grow in size until it is ready to give birth. When guppies reach adulthood after 21-30 days, they will hatch and swim freely away from their mother.

Female guppies are inherently chubby, but the increase in size due to pregnancy is a bit different.

Most notably, the abdomen begins to bulge. It can even have a slightly boxy shape. Before the guppies become pregnant and give birth, the belly may look a bit angular.

Ours Noted for you: There are other reasons why guppies' bellies may be more extensive. Illnesses such as ascites and swimbladder disease may be to blame. Pay attention to that is the most apparent difference between sick and pregnant guppies.

You can see changes in their behaviour.

The signs of pregnancy are not just physical. Many pregnant female guppies also begin to have behavioural changes.

Females tend to become quite aggressive when they are pregnant. Although they may display aggressive behaviour towards any fish that get in their way, pregnant females tend to channel most of their anger on the males.

That's because the males will often try to mate with the female even after the female is already pregnant. As the fish stage is about to birth, you will notice more extreme behavioural changes.

The first is anorexia. Guppies tend to avoid eating right before birth. If they eat, you can see them spit the food out afterwards. Pregnant females will also begin to seek refuge. She will go missing while trying to find a peaceful place to give birth.

Ours Noted for you: Guppies are very vulnerable to attack when giving birth, so they seek out quiet areas to avoid problems from other fish. These include difficulty breathing and body convulsions.


Length of time pregnancy.

The gestation period of guppies is usually short. A baby grows up in the womb for about 21 to 31 days. In rare cases, pregnancy can last up to 35 days.

The external factors and the surrounding environment will determine the reproduction factor. Everything from water temperature to food availability, and the same goes for the overall health of the fish.

The actual birthing process is much shorter. It only lasts two to six hours. It is vital to maintain good tank conditions when caring for pregnant guppies. Incorrect water parameters can delay pregnancy. In severe cases, environmental factors can end a pregnancy altogether.

Keep the tank clean and monitor the condition regularly. Guppies can give birth in standard tank conditions, but everything needs to be maintained to ensure the mother's health.

How many fries can you expect?

How many babies you will have depends on many different factors. Pregnant guppies can give birth to 10 to 50 fry. Genetics, food availability, the mother's health and a little luck will determine the number of fries you want.

Age is an important factor. Young fish that give birth for the first time tend to give birth to fewer young. The fry is usually smaller and weaker. As they age and continue to mate, female guppies often give birth to more offspring with each pregnancy.

There is no guarantee of survival rate. Some babies inevitably die soon after birth. Whether it is due to being eaten by other fish or due to natural causes, a 100% survival rate is rare. Some fry may even be stillborn. Older fish with some experience tend to have a smoother pregnancy than younger fish.

Ours Noted for you: It is an impressive fact that guppies can get pregnant quite quickly after giving birth. There can be up to eight pregnancies in a single spawning, which means that female guppies can give birth to several hundred guppies in a single season. Females can have a new litter every month! Common spawning fish can give birth to over 2,000 young in a lifetime!


Prepare the mother fish to spawn.

If you want to maximise the survival of babies, you need to take steps to prepare for this spawn. Transfer them to a separate spawning tank. These breeding tanks are different tanks that you will transfer the female to before she gives birth, which is also where you will raise the fry afterwards.

Being separated from the rest of the school will greatly reduce stress. Moreover, it will give the babies a fighting chance to survive. You don't need a large spawn tank. A small 10-gallon aquarium will fit.

Whatever you do, ensure the fry has a place to hide and avoid being eaten. Even the mother fish will try to eat her young. Many breeding tanks have slanted bottoms for the fry to pass through after leaving the womb.

Aquatic plants for the baby tank.

Smooth-leaved plants also work well. Plants such as Java moss, hornwort and grass provide plenty of cover and protection for the fry. Many aquarists find the survival rate of fry quite good with these plants in the community tank.

Once out of the womb, babies often curl up in a ball. Remove dead young fish to keep the rest healthy. The healthy ones will start swimming once they reach safety.

Guppies are significantly larger than most fish that hatch from eggs. As a result, they can eat more significant foods while still in the womb. You must ensure you have the right food to keep those kids well-fed.


Provide a suitable environment: The pregnant guppy needs a clean and well-maintained tank with plenty of hiding places, plants, and decorations. A gentle water flow and a temperature of around 75-82°F are also ideal for the well-being of the mother and the babies.

Change new water for the guppies' tank during spawning.

Continue regular water changes and filter maintenance, as dirty water can lead to serious pregnancy complications. Guppies grass should help reduce ammonia and give pregnant guppies ample hiding space.

Food for mom & babies.

The best food is young brine shrimp. It's packed with protein and fat, so prepare a batch before giving birth. You can also grow infusoria. In addition to high-quality fish scales, consider adding nutritious treats like bloodworms or brine shrimp to round out her diet before she can give birth.

Be prepared to keep guppies separately for about two to three months. At that point, they are sexually mature and ready to join larger community pools.


Caring for a pregnant guppy is a simple process, but it requires attention and care. A suitable environment, proper nutrition, and pregnancy monitoring will ensure the mother and baby's health and well-being.

After reading these few articles, we hope you have all the information you need to recognise a pregnant seven-colour. And if that's happening in your tank, here's your good news and congratulations.

Let us know if you have any other questions about the process or need help determining if you have pregnant guppies. We are always to help you here.

Read more about guppy water temp here.

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