Is My Guppy Pregnant? (How to Know)

Guppies are the most common fish species that both beginner and experienced aquarists like to have in their aquarium. Unfortunately, guppies breed a lot, and it sometimes gets challenging to detect if our guppy is pregnant or just fat. So, is my guppy pregnant? Let us find out.

There are signs to detect if your guppy is pregnant or not. The most common sign is a gravid spot behind the fin anal of its body. If pregnancy is not the reason behind the fat belly, then overeating, dropsy, infections, and constipation can be the possible reason behind that.

This article will discuss how to know when pregnant guppy will release fry and what to do when our guppy is pregnant. So let us get into it.

Key facts about guppy fish pregnancy

Guppies can breed out of control if kept together male and female.

If you have both male and female guppies in your aquarium, they will breed excessively.

There are signs to detect if your guppy is pregnant, like a big rounded belly, a dark spot behind your guppy’s anal fin, and more.

The average gestation period of pregnant guppy is 25-30 days.

The gestation period can extend if your pregnant guppy comes under stress or looks danger around them like aggressive tankmates.

Is my guppy pregnant or fat?

It is not hard to detect if your guppy is pregnant or just fat.

You have to know that if you have both male and female guppies in your tank, your guppies will mate like crazy.

Your female guppy can be pregnant even if no male guppy is present in your aquarium.

It is possible if your female guppy has mated with male guppy before adding them to your aquarium.

Many fish store keeps male and female guppies together.

It’s easy to think that guppy is pregnant when it is female, but we need other explanations for a male guppy.

There can be various reasons for your guppy looking fat which includes:

  1. Dropsy
  2. Overeating
  3. Infection
  4. Constipation
  5. Tumors

If your guppy looks fat, you should look for the signs of illness rather than thinking that it is pregnant.

Maintaining adequate water conditions and providing your guppies with a stable water condition prevents your guppies from various diseases.

How to know if a guppy is pregnant?

With just looking fat, more symptoms explain whether your guppy is pregnant.

These are the signs of guppy pregnancy:

  1. Difficulty in swimming
  2. Losing appetite
  3. Presence of gravid spot
  4. Showing hiding behavior
  5. Aggressive behavior
  6. Mating
  7. Swimming in one place
  8. Big rounded belly

If your female guppy has any or all of the signs, it is possibly pregnant, and there is nothing to worry about your guppy.

These are the signs which clearly state that your female guppy is pregnant.

An owner should know that guppies can keep the fry inside their belly for months without releasing them.

Sometimes, guppy will release 4-5 fry at a time and then stop releasing fry, but there will be more fry inside them.

It happens when your guppy is not feeling safe or is under stress. In such a case, guppy can hold releasing fry for months.

As discussed above, your guppy may be pregnant even if no male guppy is present in your aquarium.

Also, if you have both male and female guppies in one tank, they will breed out of control.

Pregnant guppy will lose its appetite also, will be aggressive and inactive at a time.

The most common way of finding if your guppy is pregnant or not is looking for a gravid spot.

If your guppy is pregnant, you will see a dark colored spot present just behind the anal fin of your guppy.

The gravid spot will become darker and extend with the coming time of releasing fry.

What to do if my guppy is pregnant?

When the female guppy gets pregnant, they start to become weak by the time of pregnancy.

Keep the aquarium clean and provide your pregnant guppy a warm and stable water temperature to live comfortably.

Keeping the aquarium clean will keep your pregnant guppy away from various illnesses.

Your pregnant guppy will refuse to eat as they will lose their appetite.

Providing them food that fulfills their all dietary needs is essential for pregnant guppy and fry.

It would be best to regularly feed your pregnant guppy live or frozen brine shrimp. You can also go for flake food or spirulina flakes.

Your guppy will not be much interested in eating during pregnancy because fry will occupy a lot of space in their belly.

But, at this time, eating is essential for your pregnant guppy. So you can provide your guppy a tiny pinch at a time for 3-4 times a day.

How long can guppy be pregnant?

A female guppy can be pregnant for around a month on average.

20-25 days is the average gestation period for guppies.

Keeping the tank water temperature between 72-82°F will prevent guppies from being pregnant for a long time.

If your guppy is under stress or feels danger around them like aggressive tankmates, they can hold releasing fry longer than the average gestation period.

It is essential to provide your guppy with good water conditions with stable water parameters to keep them from illness.

Any issues suffered by the pregnant guppy can lead to an unsuccessful pregnancy.

How to know when pregnant guppy will release fry?

It is hard to know the exact day when our pregnant guppy will release the fry.

These are some signs that you can look for knowing that soon your guppy is going to release fry:

  1. You will see the pregnant guppy will have an angular shape belly. It will look like a sharp “C” like shape.
  2. Your pregnant guppy will show hiding behavior.
  3. You will see your guppy swimming in a particular place.
  4. Your guppy will avoid eating completely. 

It is essential to separate your pregnant guppy and isolate them in a separate tank or place them in a breeder box when it’s about to release the fry.

Other tankmates in the aquarium will try to attack guppy fry and eat them.

Even the mother guppy will not hold back from eating their fry.

Place the guppy fry in a separate tank or let them live in a breeder box attached to the home aquarium.

But, placing the guppy, which has just given birth to fry, in a separate tank, is essential as the guppy will need 1-2 weeks to recover.

It is essential because the guppy will be weak for some days, and other tankmates will try to bully the guppy after giving birth.

Also read: Can Guppy Fry Survive In a Community Tank?


It is not hard to detect if your guppy is pregnant or not.

If your guppy is pregnant, it will have a dark color spot behind its anal fin, also known as a gravid spot.

Other signs are aggressive behavior, loss of appetite, big rounded belly, and presence of male guppy in a tank.

If your guppy is not pregnant and is looking fat, then there can be a problem of overeating, infections, dropsy, constipation, and indigestion.

Usually, guppy will release the fry after 23-25 days of getting pregnant. But it can be a delay if your pregnant guppy is under stress or if they see any danger around them.

Your guppy will show hiding behavior and have an angular shape like a belly, which will indicate that soon it will release the fry.

Reference: NCBI, Wikipedia,

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