Pregnant Guppy – When Do Guppies Have Babies

Guppies (Poecilia reticulata) are probably the easiest freshwater fish to breed. Breeding these live-bearing fish is a fascinating hobby because there are just so many beautiful fancy guppy breeds out there. Knowing when your guppies are pregnant can be really important, however, especially if you want to raise as many babies as possible.

This guide will teach you everything you need to know about pregnant guppy fish. So let’s get started!

Is My Guppy Pregnant?

This is a question that so many beginner fish keepers find themselves asking. If you think your guppy is pregnant, don’t worry, you’re at the right place! If you’re new to fancy guppies, it’s best to go one step back and find out whether you have a female guppy at all.

Male vs. Female Guppies – What’s The difference?

Figuring out whether your guppy is male or female can be very easy when you know where to look. Read on to learn what to look for:

  • Gonopodium The best way to tell whether your guppy is male or female is to look at the anal fin on their belly area. Male guppies have a modified anal fin consisting of 3 fused fin rays. This structure is used to transfer a sperm packet to the female guppy fish.
  • Body Colors Female guppies can have nice colors, but they usually do not show the amazing variety of colors that the males have. Most female guppies will have silvery bodies with some dull colors and markings.
  • Body Size Female guppies grow much larger than males. They can reach 2.5 inches, a whole inch larger than the males.
  • Fin Size & Shape In most cases, male guppies have longer and more colorful fins than females. Female guppies can have some color on their fins and tails, but it is usually pretty dull and the fins tend to be more rounded.

Signs Of Pregnancy

If you’re sure you’re guppy is female, the next step is to figure out if she is pregnant or not.

Guppies are livebearing fish which means they don’t lay eggs but rather give birth to free-swimming baby guppies. Male and female guppies are often kept together at the store, so if you buy a female from a mixed tank, there’s a good chance your guppy is pregnant.

So now you know how to tell which of your guppies are male and female, but how do you know if a female guppy is pregnant? Let’s take look at some of the pregnant guppy signs:

  • Gravid Spot The gravid spot is the best sign to confirm whether your female guppy is pregnant. The gravid spot is a dark marking above the female’s anal vent. All mature female guppies have a gravid spot, but it will become larger and darker on pregnant females.
  • Belly Size Changes in size and color of the guppy gravid spot are a great sign of guppy pregnancy, but you should also keep an eye on the belly size of the pregnant fish. Pregnant guppy fish develop a box-shaped belly as the pregnancy progresses.

If you have noticed these signs, congratulations, you have a pregnant female guppy! The next thing you’re probably wondering is when you can expect the baby guppy fish to be born, so let’s get into it!

Guppy Pregnancy Stages

Guppy pregnancy can be divided into different stages. Understanding the different stages of your guppy’s pregnancy will help you prepare for the birth and help you get ready to care for the guppy babies. Protim Aquatics has a wonderful video that shows the process. I’ll explain below as well in the post.

Stage 1. Mating

The first stage of guppy pregnancy is mating, and guppy breeding behavior can actually be fascinating to watch. Male guppies don’t have all those beautiful colors and fancy fins for nothing, they use them to impress the females!

Male guppies can mate by the age of about 2 months when they will start to show off and display to the female fish by swimming around them and flaring their fins in a mating ritual.

If the female is interested, the actual mating process will happen very quickly. The male will tilt his gonopodium forward and use it to transfer a sperm packet to the cloaca of the female fish.

Stage 2. Early Development

After mating the female will have a flat belly. A week into her pregnancy, her belly will start to look noticeably rounded. Her gravid spot is not very prominent or dark at this stage.

Stage 3. Growth Phase

As the pregnancy progresses over the next two weeks, the belly of your pregnant guppy will become larger until the gravid spot becomes highly visible by the third week.

Stage 4. Advanced Pregnancy

By the fourth week, the female guppy fish will look obviously pregnant. Her belly is huge and box-shaped at this time, and she is nearly ready to give birth. Look out for the following signs that your pregnant guppy fish will be giving birth very soon:

  • Pregnant female guppies look for a sheltered spot to give birth about a day before giving birth.
  • She will breathe rapidly, often at the surface.
  • You might even be able to see the dark eyes of the baby fish through the belly of the mother guppy

Stage 5. Birth

The typical guppy gestation period is 25-35 days. With so much overlap, it’s tough to plan it to an exact day, but looking out for the signs in stage 4 can help you stay prepared.

It can take a few hours for your pregnant guppy to give birth to all of her babies. The guppy fry are curled up in a ball when they are born but they will start to swim immediately if they are healthy.

After giving birth, your female guppy can produce a new brood of fry after about a month. She can do this without mating with a male guppy again because she can store sperm for many months.

How To Care For Your Pregnant Guppy & Fry

So now you know how to tell whether your guppy is a female, if your guppy is pregnant, and you know about the 5 stages of guppy pregnancy. But what happens when she gives birth? How do you care for the babies?

In this section, I’ll teach you the basics of caring for your guppy fry. Let’s dive right in!

Tank Setup & Parameters

Guppies are adaptable fish that do not have any special requirements when it comes to tank setup. A ten-gallon or larger tank is ideal for raising guppies.

Guppies can be kept in a bare bottom tank, or over a substrate of your choice, but you should use a lid/hood over your aquarium to prevent any of your fish from jumping out.

Guppies are relatively hardy aquarium fish, but they prefer the following range of water parameters:

  • pH: 7-8
  • Hardness: 8-12 dGH
  • Ammonia: 0 ppm
  • Nitrite: 0 ppm
  • Nitrate: < 20 ppm

Heating

Adult guppies can survive in a wide range of water temperatures, but I would strongly recommend using a heater to provide the perfect water temperature for your pregnant guppy and her fry.

The ideal temperature for your pregnant guppy is between 76°F and 80°F and the baby guppies will do great in the same temperatures. Make sure you pick up a heater that matches your tank size and a thermometer to keep an eye on the actual temperature, this will make dialing in the perfect conditions much easier.

Filtration

Filtration is something that many first-time guppy breeders don’t pay enough attention to. Baby guppies are not very strong swimmers, so you’ll want to use a filter that creates low water movement in their tank.

The fry are also very vulnerable to being sucked into power filters, so be sure to protect the baby fish by placing a prefilter sponge or tights over the filter’s intake. The best filter to use when raising guppy fry is a sponge filter.

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Tank Maintenance

Pregnant guppies and fry can be very sensitive to poor water quality. A 25% weekly water change is recommended to keep your nitrate levels down and will also allow you to suck up the waste from the bottom of the tank. Just be very careful to avoid sucking up any of the tiny fry!

Tips For Avoiding Predation

Guppies will breed freely in a community tank, but there’s a reason why many of the fry disappear in a few days. Most aquarium fish will happily eat these tiny baby fish, including other guppies!

If you’re OK with that, you might still get a few lucky young fish that survive to adulthood, but you’re going to want to take some steps if you’d like to see more of them survive.

Provide Cover

The simplest solution is to provide loads of cover where the babies can hide while they grow. Live plants like guppy grass and Java moss are the best for this, but ornaments and caves can also work very well.

Growing live plants provides an excellent food source for the baby fish, which will graze on microorganisms that live on the leaves. You will need aquarium lights to successfully grow plants, of course.

Guppy Grass (Najas indica)

Guppy Grass is a great plant for breeders and beginners. It is stress free, grows fast, and helps remove nutrients in an aquarium

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Standard aquarium lighting will do fine for easy plants like guppy grass, although you’ll want to set your lights on a 6-8 hour per day timer and provide them with fertilizer to keep them growing well.

Set Up a Separate Breeding Tank

For fishkeepers who want to get serious about breeding guppies, a separate tank is the best way to go. This allows you to separate the babies from the other fish that will see them as a tasty snack. This method can be pretty stressful for the pregnant female guppy, but it definitely reduces the chance of your guppy fry being eaten.

Adult guppies don’t need a huge tank, and you can easily keep a trio in a 5 to 10-gallon setup and raise their fry in a 15-20 gallon grow-out tank. Once your female guppy is pregnant, you can move her into the larger birthing tank until she gives birth. The female can be moved back to the separate breeding tank once the fry are born.

A bare bottom setup is best for your fry grow-out tank because it is easier to clean and makes it easier to see and count your guppy fry. This tank should be equipped with a gentle sponge filter, and a heater, and include some java moss or guppy grass.

Use A Breeding Box

It is possible to let your female guppy give birth in your main tank, but still keep the newborn guppies safe from hungry mouths. Breeder boxes allow you to separate your pregnant female guppies from their fry immediately after they give birth.

The healthy fry can swim through into a separate chamber where the other fish can’t reach them. The young fry can be kept in the breeding box for a few days but should be moved to a safe place or released into a tank with plenty of cover after that.

Feeding Your Pregnant Guppy

Guppies are easy to feed because they thrive on a diet of high-quality fish flakes. Pregnant guppies should be provided with a more balanced diet to ensure the health and growth of the fry, however.

Female guppies are omnivorous fish, so feed them fish flakes, frozen brine shrimp, and small amounts of blanched vegetables to keep them in top condition.

Feeding Your Guppy Fry

Guppies don’t make great parents, so it’s a good thing baby guppies are born ready to fend for themselves!

The best food for baby guppies is baby brine shrimp, which can be provided twice per day. The babies will also feed on powdered flakes and forage for themselves on microorganisms growing on live plants.

How To Avoid Pregnant Guppy Fish

If you do not want your guppies to breed, you’re going to need to separate the females from the other fish, but be aware that a pregnant guppy can drop several litters of fry after a single mating. The good news is that many fish-keeping stores will be happy to buy your healthy young guppies from you.

Consider keeping only males if you haven’t already bought your guppies and you really do not want them to breed. Even female guppies can be purchased and already be pregnant prior to place them into your display tank.

FAQs

How long is a guppy pregnant for?

Most female guppies will be pregnant for 21 – 31 days, although sometimes pregnant guppies will carry babies for as long as 35 days.

How long does it take for a guppy to give birth?

Guppies often stay in labor for many hours but it really depends on how many fry your pregnant guppy is carrying.

How many babies does a pregnant guppy have?

Guppies usually give birth to between 5 and 50 babies. The most important factor that determines the number of babies she can produce is her size. Some female guppies have given birth to over 200 fry in a single litter!

Can female guppies get pregnant without a male?

A female guppy cannot get pregnant without mating with a male guppy at least once. She can, however, give birth to many litters after just a single mating. This means it is possible to buy a single female guppy from the pet store and have several litters of babies over the next few months!

Do all female guppies have gravid spots?

All female guppies have a gravid spot, whether they are pregnant or not. It might not be visible on dark-colored breeds like tuxedo guppies though. This dark area becomes much larger and more visible when a female guppy fish is pregnant.

How can you tell if a guppy is gravid?

The best markers to look out for on a pregnant guppy are a large, dark marking (gravid spot) just above the female’s anal vent. Your guppy’s belly will also grow large and box-shaped as the babies grow.

Why is my pregnant guppy’s gravid spot orange?

The gravid spot of a pregnant guppy is usually darker than the rest of her belly. This spot can range from orange to black, depending on the stage of her pregnancy and even the amount of light in the aquarium.

Final Thoughts

Having a pregnant guppy is always exciting because you just never know how many fry you’re going to get or what kind of colors and patterns they might have when they grow up! Caring for your pregnant guppy is easy, and with the tips in this guide, you can give the baby guppy fish their best chance of survival. Happy guppy breeding!

Do you have pregnant guppies in your fish tank? Share your experiences in the comments below!

by Mark

Mark is the founder of Aquarium Store Depot. He started in the aquarium hobby at the age of 11 and along the way worked at local fish stores. He has kept freshwater tanks, ponds, and reef tanks for over 25 years. His site was created to share his knowledge and unique teaching style on a larger scale. He has worked on making aquarium and pond keeping approachable. Mark has been featured in two books about aquarium keeping - both best sellers on Amazon. Each year, he continues to help his readers and clients with knowledge, professional builds, and troubleshooting.

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