How To Tell a Guppy Is Pregnant

How to tell a guppy is pregnant?

Is she avoiding alcohol on social occasions and has morning sickness often?

Being able to identify when a guppy is about to give birth allows you to prepare and ensures the well-being of both the mother and the fry.

So let’s dive right in (yes, it’s a terrible pun- I know) and figure out how to tell a guppy is pregnant. 

TL;DR Short Version

How To Tell a Guppy Is Pregnant

There’s an old say that goes: “if its a guppy- then she’s pregnant”. You can safely assume that any female you keep in a co-ed tank will be pregnant. Females will spend most of their lives pregnant. Here are a couple of signs too:

  • Belly bulge: Guppies get a bigger belly when they are pregnant.
  • Dark gravid spot: The gravid spot, located near the guppy’s anal fin, darkens when she is pregnant.
  • Boxy shape: As the guppy gets closer to giving birth, her abdomen will become more square-shaped.
  • Eye spots: If you can see little dots in the gravid spot, those are the eyes of the baby guppies.
  • Behavioral changes: Pregnant guppies may become more reclusive or withdrawn.

Pcitures: How To Tell A Guppy Is Pregnant

A pregnant guppy's gravid spot. by looking at the gravid spot you be able to tell whether it's male or female.

A pregnant guppy’s gravid spot gets darker as the pregnancy progresses

Looking at a female’s belly is another way to tell a guppy is pregnant.

Guppy Pregnancy Cycle

The guppy pregnancy cycle takes about 20 to 30 days. 

Guppies have gotten the reputation of water bunnies. They breed fast, they breed a lot and they just keep going. You can plan on each female giving birth to 20-100 fry every 30 days.

The process will usually start when the male starts courting the female. Males are known to be pretty persistent- which is why you want to keep the right ratio of 2-3 females per 1 male. 

Physical Changes

How To Tell A Guppy Is Pregnant- Part 1

As the pregnancy progresses, you may notice several physical changes in a pregnant guppy:

Enlarged Abdomen

The vent, or anal opening, of a pregnant guppy may appear distended or swollen as the time of delivery approaches. This is a result of the fry positioning themselves for birth.

Darkened Gravid Spot

The gravid spot, located near the rear of the female guppy, may darken or become more prominent. This dark spot is the result of the developing fry showing through the mother’s translucent body.

Distended Vent

One of the most apparent signs of pregnancy is an enlarged abdomen. The pregnant guppy’s belly becomes noticeably larger as the fry develops inside.

Pregnant Guppy Behavior Change

How To Tell A Guppy Is Pregnant- Part 2

In addition to physical changes, a pregnant guppy may also exhibit certain behavioral changes

Decreased Appetite

Some pregnant guppies may experience a decreased appetite as they near the end of their gestation period.

It is not uncommon for them to eat less or even refuse food altogether.

Isolation or Hiding

Social isolation is another way of to tell a guppy is pregnant. 

This behavior is their instinctual response to protect themselves and their fry.

This is a great time for you to make sure your aquarium has plenty of hiding spots.

Observing Frequent Contractions

As the time for delivery approaches, a pregnant guppy may display visible contractions. These contractions can be observed as the female’s body periodically tenses up, causing ripples or movements along her abdomen.

This is your sign that labor is imminent.

Remember that these signs can vary from guppy to guppy, and every fish will have its own set of signs.

It’s essential to monitor your pregnant guppy closely and look for a combination of these signs to determine when she is likely to give birth.

Preparing for Birth

Now that you’re certain that your guppy is close to giving birth, there are a few steps you can take to ensure a smooth process:

Create Space

Create a separate birthing or breeding box within the aquarium.

This allows your pregnant guppy to give birth in a safe and controlled environment, preventing other fish from preying on the fry.

More Hiding Spaces

Place some fine-leaved plants or mesh in the birthing box to provide hiding spots for the fry. This helps to reduce stress and increases their chances of survival.

Maintain Water Quality

Ensure that the water quality in the birthing box and the main aquarium is optimal.

Change the water regularly and make sure your filtration system works.

This will help maintain good water conditions for the mother and fry.

Postnatal Care

Once the guppy has given birth, remove the mother from the birthing box and return her to the main aquarium.

At this point, you can start providing appropriate food for the fry, such as powdered or finely crushed flakes, brine shrimp nauplii, or commercially available fry food.

Postnatal Care

Continue to feed her normal diet

Female guppies are more sensitive to water quality and temperature when it comes to dropping (aka giving birth) then food availabilty. 


We’ve covered quite a bit here- so let’s recap.

You’ll be able to tell your guppy is pregnant when her belly grows and her gravid spot becomes darker. 

She will most likely become more shy and will seek shelter more often, rather than socialize. 

Do know that guppies are pregnant very very often. They are almost always pregnant- that is just the way it is. 

Now that you have that knowledge- let me ask for a personal favor:

Is this the first time your guppy is pregnant? Please let me know in the comments!

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