Why Do Bettas Make Bubbles? The Betta Bubble Nest.


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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 does my betta blow bubbles?’

Despite their aggressiveness, male bettas have some unusual behaviors, such as blowing bubbles. The male betta can also become quite attached to the bubbles he has blown, so what’s the deal? Why do bettas blow bubbles?

Male betta fish make bubbles to form a nest. A betta fish bubble nest is a floating dome of bubbles created to attract potential mates. It is the male’s way of showing off his ability to be a good mate for the female. The male can become very protective and territorial over his bubble nest.

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

If you want to understand more about why bettas blow bubbles and make bubble 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.

What Is A Betta Bubble Nest

A betta bubble nest is a floating object in the water that has been covered with bubbles by a male betta fish. 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 bubble nest can take up to three hours to make but should be finished within an hour if the female is present. Betta fish bubble nests are very common and reported by many betta owners. Very anxious fish tend not to exhibit this behavior as commonly.

Many new betta owners report seeing bubbles floating at the water’s surface or notice their betta fish staying near the surface of the water, gulping air before they start to blow bubbles, and may become concerned that their fish does not have enough oxygen.

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

Most bettas will blow bubble nests when they are in good health and happy in their tank so take some comfort in knowing this behavior is perfectly fine and natural.

Why Do Betta Fish Make Bubble Nests

Bettas will create bubble nests throughout the day, building them on floating objects or plants in an aquarium. Bubble nests may also be created next to other previously made bubble nests by separate males (in cases of overcrowding). When a betta fish builds a bubble nest, it is called “attempting courtship” by betta breeders.

The bubble nests are also used to keep the fertilized eggs during breeding and the fry after hatching. In fact, bubbles are even thought to help protect against fungus and bacteria that might hurt the eggs and fry.

Why Do Male Bettas Blow Bubbles

People often ask why male betta fish make 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.

Do Betta Fish Blow Bubbles When 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 for the opposite reason. If oxygen levels in the water are low because of poor tank conditions, excess algae, overstocking, or other oxygen-depleting reasons, then betta fish can 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 will create plenty of bubbles as it is 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 towards the rear of the fish, just below its gills. When the betta uses this organ, it widens to take in water. It then contracts to expel that same water back outside the fish with great force and speed, creating a bubbling effect.

The actual process of building a bubble nest begins when the male betta fish tries to make himself look as large and pretty as possible by flaring his fins. He then starts swimming around in a circle over the fine-grain substrate on the bottom of his aquarium or pond. Sometimes he may do this for hours before getting anywhere near creating a nest.

The male betta will go through several different stages of nest building before he 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).

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 his bubble 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. The windows are kept very small so that the male betta can guard them easily and keep other males out.

What Happens When The Bubble Nest Building Is Complete

Once a male betta’s bubble nest has been built, the male betta 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 bubble 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 this 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 bubble nest and you have a female to introduce him to, I have 2 other articles: How Long are Betta Fish Pregnant For, 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.

You can also tell by whether his fins are flared and if he is swimming erratically. This is a male who has decided that it is time to start building a bubble nest.

If you notice your bettas 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 a male and female betta to create a bubble nest together, it is much more common for the female to lay her eggs in his nest. In fact, this often happens when two or more females are kept in one aquarium with only one male.

Should You Remove A Betta Bubble Nest

There is no real need to remove a betta’s bubble nest after he has finished building it. However, some recommend doing this so that the male won’t feel so territorial and be more likely to cooperate with other fish in the tank.

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.


All bettas can build bubble nests to attract a mate. It 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 bubble nests, 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 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.

Hopefully, you have found this article helpful and informative, and you now have a better understanding of why your betta fish is making bubble nests.

Frequently Asked Questions

Jon O'Connell

I have kept both marine and freshwater fish and set up almost 100 aquariums. Happy to share my knowledge and experience to help others enjoy keeping healthy and happy fish.

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