How To Selectively Breed Guppies (And Should You?)

Last Updated on 2023-05-24

Are you interested in knowing how to selectively breed guppies? If so, then you’ve found the right article. Not only will you find out the different methods of selective breeding, but you’ll also learn how to set up the tank correctly for them, how to pick healthy guppies, what tank you’ll need, and the best thing to do with unwanted fry.

So keep reading to find out everything you need to know!

What Is Selective Breeding?

Before you begin selectively breeding your guppies, it’s a good idea to know exactly what selective breeding is. Selective breeding is when you breed guppies that have certain traits that you want to be passed down to their fry.

Ideally, not only will the characteristics you want to be passed down, but they’ll also become more amplified and desirable.

(Interested to know whether guppies eat their babies?)

How To Selectively Breed Your Guppies

If you’re going to selectively breed guppies, then there are a number of things you’ll need to know. First of all, you’ll need to know how to select the right guppies for breeding, and once you’ve done that, you’ll also need to decide what method of breeding you’re going to choose as well!

So let’s start with the basics.

Selecting The Guppies

When you’re selecting the guppies, the most basic thing you’re going to need to understand is that you tend to pay for what you get. If you buy cheap common guppies, then the chances of breeding quality specimens are going to be extremely small.

Even if on the outside they look great, they may not have great lifespans or may suffer from health issues that have been passed down.

For the most part, you’re going to need to buy your guppies from a reputable breeder. But it’s important to know that they don’t come cheap. Sometimes a good pair of breeding guppies can cost $60 or more.

You should also try to pick guppies whose lineage is known. This way, you know that they’re going to be healthy specimens and produce healthy offspring with the characteristics you’re looking for.

One more thing you’ll need to know is that these guppies are often a lot more sensitive to the water parameters than other guppies. So make sure that you’re keeping the water levels perfect.

Set Your Goal

Before purchasing your guppies, you should set a goal for what you want the outcome to be. Do you want the most vibrant and colorful guppies? Maybe you’re looking for guppies that have beautiful flowing tails. Or perhaps both. Whatever your plan, make sure you stick to it and see it through until the end.

Once you know exactly what you want, figure out how many generations you are going to breed for each characteristic. For example, if you want to breed guppies that are extremely colorful with long flowing tails, then start by breeding only colorful guppies for 5-6 generations before breeding them for their longer tails.

If you keep chopping and changing in between, then you’ll most likely end up with guppies that aren’t particularly colorful or don’t have fins that are special in any way.

If you’re desperate, then you can set up more than one aquarium. In each aquarium, start breeding your guppies for the characteristics you want. For example, have one aquarium purely for color and one purely for tail length.

How Many Guppies Should You Start With?

When you’re starting, you should try keeping 1 male with 2 females. This way, you can have the main female you want to breed, and one to make sure she’s not becoming harassed too much. Once she becomes pregnant, you can remove the male from the tank and place him into another one. This will help reduce her stress which is vital for her pregnancy.

(Find out how to stop guppies from dying after giving birth.)

How Many Tanks Will You Need?

When it comes to selectively breeding guppies, the more tanks you have, the better. This way, you’re going to be able to separate each batch of guppies you have as well as keep the old batches in case you need to back cross when breeding (which you’ll find out about soon).

The minimum you should start with is 8, for the best chances of success; however, more is better to keep them separated. If you’re going to use less than 8, you may still have success, but it will be much harder to keep track of all the guppies you’ve been breeding.

Setting Up The Tank

When you’re setting up your guppy tank, you’ll need to make sure it’s perfect. When breeding guppies, you shouldn’t go for a tank any smaller than 10 gallons. As well as this, you’ll also need to add a filter to the tank to keep the water pristine, as well as perform frequent water changes.

As well as making sure the water is clean with a filter, you’ll have to add a heater as well. When you’re breeding guppies, it’s a good idea to keep the water warmer than it normally would be. Female guppies often suffer from chilling when they’re pregnant, which can increase the risk of disease.

Because of this, you should keep the temperature in the tank at around 78°F.

Lastly, you’ll also need to provide an area your guppy fry can feel safe when they’re born. You should add duckweed to the tank as well as plants to give them plenty of places to hide. This is even more crucial if you don’t plan on removing the parents from the tank, as they will end up trying to eat the babies.

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Different Methods Of Guppy Breeding

Next, you’ll need to figure out which method of guppy breeding you’re going to try. There are a few different types of breeding you will need to consider before you begin. And here they are:

Line Breeding/Inbreeding

The first method which often yields the best results is inbreeding. This is where you breed guppies that are related to each other.

The characteristics that you want are much more likely to be passed down. Just make sure that when you’re line-breeding, you only let the females reproduce with the fathers and don’t let the males reproduce with the mothers. This way, you reduce the chance of ending up with specimens that you don’t want.

However, the problem with line breeding and inbreeding is that your guppies may be more likely to suffer from health issues and deformities. You’ll be able to tell when you’re inbreeding too much if you notice that a lot of your guppies start to become infertile. After infertility, they’ll also begin to exhibit curved spines and other deformities more frequently.

Lastly, the best results of line breeding often come from first-degree relatives, such as the parents or full siblings.

Guppy Out Crossing

The main benefit of outcrossing is to keep your guppies healthy and reduce the risk of deformities. Guppy outcrossing involves bringing in unrelated guppies with similar traits or traits you want. This way, you’re going to increase the chances of the traits you want being successfully passed down.

You won’t need to perform outcrossing too much; every 4-5 generations should be enough to keep the genetic healthiness of your guppies intact while also making sure that you don’t lose the traits that you want.

Guppy Back Crossing

Guppy back crossing is the final method of breeding that you may need to utilize. Back crossing is where you go back a few generations to breed your current generation of guppies.

Back crossing should be used when your new generations of guppies start to show unwanted traits. When this happens, simply go back up the lineage to their ancestors, and breed them again. Doing this will help reestablish the traits you want and help to get rid of the ones that you don’t.

However, don’t expect back crossing to work instantly. Sometimes it’s going to take a few tries before you get the traits that you want.

This is why it’s important to keep the best of your guppies from past strains.

(Find out whether guppies can lay eggs.)

Selecting The Right Guppies

Before you begin breeding your guppies, you should ensure that you’re selecting the healthiest guppies with the most dominant traits you want. Harem breeding is not recommended. Not only will you begin to get confused, but you’re much more likely to stress your female out and end up with fish that you don’t want.

You should wait for all the males in your tank to reach maturity instead of just picking the first male that does. Oftentimes, the males that mature later have much better coloration and size than the early maturers.

When it comes to picking the right female, it can be a little bit more difficult. You should breed a few different females with your male guppy. Once you’ve done this, raise the different batches of fry in different tanks. Whichever female produces the best fry is the female you should use moving forward.

Keeping A Record

Breeding guppies is a long process that can become confusing quickly; if you’re going to breed them, you need to keep a record of everything to make breeding as easy as possible.

Some great ways to do this are by giving your guppy a number or letter to identify them. Make sure you make the tank therein with the identifier you’ve given them.

Make a note of the relationships the guppies have with each other. For example, which their brothers, sisters, fathers, and mothers are. You can do this in a notebook you keep nearby. As well as this, you should also describe what their good traits are and what makes them stand out.

And lastly, it’s also a good idea to keep photos and videos of your guppies so you can see the progress you’re making and compare it to new batches.

If this method doesn’t work for you, then you should come up with a method that does. Because if you don’t track it properly, then the chances of breeding guppies successfully shrink.

What To Do With Unwanted Guppies

Here’s the issue with selectively breeding guppies. Most of the guppies you breed aren’t going to make the cut, so you have to make a moral decision about what you want to do with the ones that don’t.

Ideally, you should try selling them to fish keepers or giving them away to hobbyists. If they’re deformed or sick in some way, then your best choice is to euthanize them. However, this is one of the reasons it’s so important to crossbreed, to reduce the chances of this happening.

Lastly, if the guppies are still small enough, you can try feeding them to bigger fish in another tank.


Now you know what you need to do to selectively breed guppies successfully. However, it is important to remember that it’s not for the impatient. Breeding high-quality guppy specimens is going to take a lot of time, and the chances are you’re going to make a lot of mistakes along the way.

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