Why Do Bettas Make Bubble Nests

Betta fish are magnificent creatures with their unique colorings and long flowing tails among the male fish. One of the most common questions I am asked about these beautiful fish is, ‘Why do betta fish blow bubbles?’

Male betta fish blow bubbles to create a nest. Betta bubble nests are floating domes of bubbles created to protect newly laid eggs, and also the male’s way of showing off his ability to be a good mate for the female. Male bettas can become very protective and territorial over their bubble nests.


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There are other reasons why betta fish blow bubbles, such as marking their territory and warning other male bettas away. The bubble nest itself is used to protect the young betta fry before they hatch and in the few days after hatching.

If you want to learn more about why bettas blow bubbles and make nests, this article will give you a complete insight into this unusual but interesting behavior.

Make sure to check out our Betta Fish Care Guide And Species Overview.

Why Do Bettas Make Bubbles
What Is A Betta Bubble Nest

Floating debris is usually covered with bubbles by a male betta to create a bubble nest. It is the only thing that males produce from their sperm-producing organs or papilla.

The bubbling is caused by the rapid beating of specialized muscles (opercular cilia). These bubbles are used to attract a mate and are an important part of the mating process.

A betta can take up to three hours to make a bubble nest, but it is often finished within an hour if a female is present.

what is a betta bubble nest
A male betta blowing a bubble nest

Why Do Betta Fish Make Bubble Nests

When a betta fish builds a bubble nest, it is called “attempting courtship.” The process of building a nest is only part of the courtship behavior, but it is very important for the betta to get it right. A female betta will inspect the nest closely before choosing to mate.

Bubble nests are also used to hold the fertilized eggs which were created during mating, and will protect the newly hatched fry. The bubble nest can help protect against fungus and bacteria that might hurt the eggs and fry.

Bubble nest building is usually done throughout the day and is typically built on floating objects or plants within an aquarium.

Why Do Male Bettas Blow Bubbles

People often ask why male betta fish blow bubbles, and the truth is that both male and female betta fish can blow bubbles.

A male betta will build a bubble nest to attract females as it is part of the courtship behavior, and he goes through several stages of showing off its beauty before mating with her.

Males can be very territorial if their bubble nest is next to those of other males and if the bubbles are very close together.

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Do Betta Fish Blow Bubbles When They Are Happy

Some betta fish will build bubble nests even when they don’t have a mating pair. Tank conditions need to be good and the water needs to be clean and they will build their nests as a sign of happiness.

Betta fish may also blow excessive bubbles if oxygen levels in the water are low due to poor tank conditions, excess algae, overstocking, or other oxygen-depleting reasons. When there is a lack of oxygen, betta fish will breathe oxygen from the air.

Air-breathing is possible because of a labyrinth organ that I will discuss below. Oxygen from the air is not the same as the dissolved oxygen found in the water, and it creates plenty of bubbles when expelled.

How Do Bettas Build Bubble Nests

While the male betta creates its bubble nests out of very small air bubbles, the actual nest is usually covered with a fine substrate (such as the fine-grain sand found at pet stores). This allows a smooth surface for the nest to form on without being too bumpy or rough to hurt the eggs or fry.

Bettas have a labyrinth organ that enables betta fish to breathe air from the atmosphere, and it is also used for creating bubbles. It is located just below the gills. When the betta uses this organ, it widens to take in oxygen. It then contracts to expel that oxygen and create a bubbling effect.

Male betta fish go through several different stages of bubble nest building before it is finished.

First, he will prepare a place to make the bubble nest by gathering the fine-grain substrate in his mouth, bringing it to the surface where he blows it out into a pile on top of the water (the finer the substrate, the better it will work as a base for the nest). Betta fish will also use leaves or other types of floating debris to anchor the nest.

Next, he will take the air out of his mouth and blow it into the substrate pile, where he spreads it out to give himself more room to blow more air. He may also pick up larger objects with his mouth (like pebbles or leaves) and place them on the pile to better shape the bubble nest.

The male betta will keep blowing air into the substrate until the nest is completed. He may blow small amounts of substrate out as he works, but most of it remains inside the nest with just a few “windows” open so that more air can come in.

What Happens When The Bubble Nest Building Is Complete

Once a male betta fish bubble nest has been built, he will go to the surface and flap his fins rapidly to draw attention to it. He may also turn around in circles in full view of any female betta fish that might be interested (he’s showing off).

Below is an interesting video of the mating process of betta fish.

Betta Fish Mating and using a bubble nest.

At this point, the male will begin to feel very threatened if he sees another male near his nest. However, if there are other females around (and no other males), he may allow a female betta fish to swim into his bubble nest for inspection. If she is interested in mating with him instead of one of the other fish in the tank, she will go to the bottom of the bubble nest and lay her eggs.

If the female betta does not like the male, she will swim away and either find another bubble nest to lay her eggs in or lay them on plants in the aquarium.

If your betta has built a nest and you have a female to introduce him to, I have 2 other articles: How Long are Betta Fish Pregnant, and Baby Betta Fish (Care and Feeding Guide) which both contain useful information about betta breeding.

How Can You Tell If A Betta Is Building A Bubble Nest

You can tell if a betta is building a bubble nest by looking at whether or not it is gathering substrate from the bottom of the tank, or If it is moving around with something in its mouth, that could be either food or building material for its nest.

If your betta’s fins are flared and if he is swimming erratically, and blowing bubbles near the surface, there is a good chance that a nest is under construction.

Do Female Bettas Make Bubble Nests

You may be surprised, but you can also find female bettas building bubble nests! In fact, they can do this whenever they choose (unlike the male bettas). Instead of using their sperm-producing organs or papilla, a female betta uses her ovipositor. This is used to lay eggs in the bubble nest and for laying unfertilized eggs called “slug” eggs.

The female betta will go through the same stages as the male when making her bubble nest, gathering the substrate in her mouth to build it up and blowing air into it with her opercula muscles. The only difference is that a bubble nest made by a female betta usually doesn’t have much detail because she is not trying to woo any other female bettas.

While it is possible for both male and female betta fish to make a bubble nest, it is much more common for the male as it forms part of his mating ritual.

Should You Remove A Betta Bubble Nest

There is no need to remove betta fish bubble nests after they have been built, however, some recommend removing them to prevent the male becoming aggressive and territorial toward other fish when trying to protect their nests.

If your betta is in a tank by itself, you can leave the nest alone, but if your betta is in a community tank, you should monitor his behavior toward the other fish in the tank. If your betta’s aggression has increased, you should remove the nest.

Destroying A Betta Bubble Nest

You can remove and destroy your betta’s nest if you feel he would be happier without it. When removing the nest, be cautious since male bettas will become extremely aggressive about their home, even if it no longer has any function.

There are also various opinions on whether or not a betta will be able to rebuild its bubble nest. Some believe it is very likely, while others say that the male may never build another one.


The betta fish bubble nest is central to the betta mating ritual. It is used to attract a mate, and to protect the eggs before they hatch.

Bubble nest building is a very natural behavior that you can observe in your male betta. There are many instances in which a female betta will build her own bubble nest, although she may not make them as elaborately as the male.

If you want to encourage your betta to make a bubble nest, you need to make sure that you have set up your betta tank the right way so that they feel comfortable and happy in their environment.

Not all bettas will build a nest, so if you find one in your betta tank, you should consider yourself lucky! Keep your eyes open for the other stages of the mating ritual as well! If you have a male and female betta living together, keep an eye open for some betta fry as well.

If you have a breeding pair, even if it was not your intention to breed your betta, it may be useful to have a breeding tank, especially if you keep your betta fish in a community tank. You could also start a betta sorority tank with several females.

You may find you are more successful in breeding by using a separate tank, and it will also protect the newly hatched young from larger fish.

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Jon O'Connell

I have kept both marine and freshwater fish and set up almost 100 aquariums. Although I am no longer doing it professionally, I hope I can help others to enjoy keeping happy, healthy fish by sharing my many years of experience.

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