How to Stop Your Guppies From Breeding?

All fish owners understand the importance of water quality, temperature, and proper feeding when it comes to guppies. But few guppy lovers realize how much of an impact the guppy’s breeding behavior can have on the population.

Guppies can get pregnant monthly, with a gestating period of 21-30 days. They will generally deliver between 5 and 30 fry and, on occasion, can deliver more than 100 or even close to 200. You can easily ignore the breeding since most fry will die soon after birth in the main tank.

The other guppies will hunt them down.

But this is, by no means, a long-term solution. Eventually, the fry will overrun the tank, especially if you have more than one female giving birth at once. So, you will need to handle the matter since overcrowding will hurt the guppy population.

Here are the options available to help you prevent overcrowding and control your guppies’ breeding:

Remove The Female From The Tank

This method implies that you need to identify guppy pregnancy ahead of time and act as soon as the labor sets in. There are several signs to watch out for, including:

  • Inflated belly – This isn’t a pregnancy sign in and of itself. An inflated belly can signify a variety of issues, including constipation, dropsy, and other medical conditions. But the chances for pregnancy are higher when the guppy doesn’t show any other symptom of disease.
  • Swimming in place or floating – This behavior generally occurs when the labor sets in. The female will experience pain and discomfort and will stay still to minimize the sensation. You may also see subtle jerking as the body convulses slightly.
  • Looking to hide – Guppy females will look for hiding spots when the labor begins. It is a purely instinctive drive as the female attempts to provide the fry with a secure environment.
  • Loss of appetite – The female will stop eating when the labor starts.
  • Look for the pregnancy spot – This is a dark area, generally black, in the lower part of the female’s abdomen. It is the most compelling sign of pregnancy since all guppy females will display the pregnancy spot.

As soon as you’ve decided that the guppy is about to deliver, remove it from the tank. You should do this for several reasons, including:

  • Protecting the fry from the main populationAll fish, including adult guppies, will see fry as food. Guppies have no problem with cannibalism, and even the parents are known sometimes to consume their own offspring.
  • Allowing the fry to grow faster – Guppy fry will consume the same food as the adults, but in different proportions. They typically require more fat and protein and need more often feeding, sometimes 3 times more often than adults. This means that you will have to feed your guppy fry up to 5 times per day. Living in a separate environment, with no stress of threats from other fish, will allow the fry to grow faster and bigger. They should be ready to join the adults in the main tank at about 2 – 3 weeks of age.
  • Allows you to control the fry population – Moving the fry into a different tank will allow you to decide how many you want to keep. It will also allow you to choose the ones with the most impressive colors to enhance the population’s gene pool.

Have a Female-Only Tank

This might sound like an easy fix until you realize that males are way prettier than the females. Why is this even an option worth considering, might you ask? Well, because a male-only aquarium comes with its own challenges, which we will discuss when we get there.

Having a female-only aquarium is definitely an option worth having, despite your tank lacking color as a result. One thing to look out for is gender misidentification. Leave one male in, and you will have soled close to nothing. That one male will get very busy shortly, especially since it has no competition from other males.

The good news is that females are rarely combative and will get along with each other quite well. This isn’t the case with guppy males, as I will explain shortly.

Have a Male-Only Tank

This option is way more popular among guppy lovers for several reasons. One would be that male guppies have thinner and longer bodies, giving them a unique graciousness during swimming. Females tend to be larger and bulkier.

The other has to do with the male’s coloring. The male guppy is generally way more colorful than the female. The coloring helps them during mating, along with their ballerina moves meant to impress the female.

The only problem with having a male-only tank is the males’ innate aggression and territorial behavior. Naturally, guppy males don’t go along with other males. You will need to watch the tank dynamics carefully to prevent bullying and attacks, which may happen from time to time.

I suggest removing any guppy male that shows extremely aggressive behavior. Otherwise, it’s a matter of time until something unfortunate happens.

How To Differentiate Between Guppy Males and Females?

As I’ve already explained, knowing the males from the females is essential to prevent any unwanted pregnancy. One male left in a female-oriented tank can spell multiple pregnancies soon.

Some of the most noticeable differences are physical. These include the male’s elongated tail fin, the female’s bulkier and bigger body, and the male’s coloring. Males also have larger and more impressive tail fins compared to female guppies.

Once you’ve got the genders down, you can separate the fish successfully, eliminating the risk of unwanted guppy pregnancy.

What to do With Guppy Fry?

The problem is that not all plans go according to…plan. Sometimes, you just miss a male, and your guppies get pregnant. Other times, they mate before you can separate them, and you’re unaware of the issue. What you have now is the present which is filled with unplanned guppy fry.

The natural question will immediately arise – What do I do with them?

I have 4 options for you:

  1. Use them as live bait – Simply let Mother Nature handle the situation. Allow the female to give birth in the main tank and watch life unfolding. Most, if not all, guppy fry will fall prey to the adults who won’t be able to differentiate between fry and any other live food. The fry aren’t as susceptible to death by devouring in the wild, where they have more space to run and hide. The smaller tank will drastically reduce their chances of remaining alive for too long.
  2. Keep the good, dispose of the bad – By bad, I mean ‘those you don’t like.’ You may think you don’t want guppy fry right now, but wait for a couple of weeks for them to grow a bit. Separate them from the adult population and allow them the space and food to grow. You might find a couple with truly stunning genetics that you can use to enhance your group’s genetic pool. You can turn the rest into live bait for your adult guppies or even turn them into protein paste, along with other ingredients.
  3. Give them away – Maybe you have friends or acquaintances with aquariums looking for new additions. You might find someone who will appreciate them. Or maybe they haven’t decided whether to get an aquarium, and your extra fry will convince them. Either way, save the guppy fry for a couple of days and let the news fly.
  4. Turn them into profit – The internet market is filled with people looking for guppies to buy. If you were already set to throw the guppy fry away, you’re clearly in the mindset to sell them cheaper. This will help you get rid of them fast and do some good in the process.


As I have explained, you have several tools at your disposal to prevent your guppy population from multiplying. If you can’t prevent pregnancy with all your precautions, it’s good to know that you still have options available.

This article provides you with the key tools for maintaining your guppy population under control.

avatar Noah
I’m Noah, chief editor at VIVO Pets and the proud owner of a playful, energetic husky (Max). I’ve been a volunteer at Rex Animal Rescue for over 2 years. I love learning and writing about different animals that can be kept as pets. read more...

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