Betta fish are one of the most popular fish species in the aquarium industry. They have large, flowing fins and come in a variety of colors.
In the wild, bettas most often live in rice paddies. They sometimes find themselves in ditches, slow-moving rivers, and clogged waterways. The areas they inhabit are stagnant or slow-moving because bettas are poor swimmers.
Yet, these conditions are perfect for building bubble nests.
Male bettas put a lot of effort into creating their nests. They blow air bubbles from their mouths. Their saliva helps the bubbles stick together. The nest-building behavior can be baffling to new betta owners. Still, bettas have a very good reason for building these nests.
What Is A Bubble Nest?
Anyone with a betta is likely familiar with the bubbles they create at the surface of their tanks. Many new betta owners are unfamiliar with what these bubbles mean.
Bubble nests are entirely normal and are actually a good sign.
Bubbles are not a sign that the betta is sick or that the tank is dirty.
How Do Bettas Make A Bubble Nest?
Bettas are unique from most fish in that they have a labyrinth organ. They use the labyrinth organ to breathe air. They will drown if they are unable to surface once in a while.
Periodically, bettas will swim to the surface to gulp some air.
They use their labyrinth organ to blow bubbles.
To make the nest, bettas blow bubbles from their mouths, one by one. The bubbles float to the surface and stick to the glass, plants, or decorations resting at the top. As the betta makes more bubbles, they stick together to form a thick layer.
Occasionally, bubbles pop, and bettas must constantly replace them.
What Do Bubble Nests Look Like?
The bubbles are transparent: they comprise air and mucus.
No bubbles are the same. They appear somewhat different depending on the male creating them.
Some are larger and look distinctly bubble-like. Others are smaller, making the nest look like foam.
Most bettas make their nests in the corner of their tank. Sometimes, they create nests large enough to spill out into the middle of the tank.
Some bettas make nests in a thin, single layer that spreads out more widely across the tank. Other bettas stack their bubbles under each other to create a thicker nest.
Researchers believe that the appearance of a bubble nest may depend on the male’s size. It may also depend on how much space is available.
Smaller, younger males may make smaller bubble nests so they don’t take up as much room. Larger and more confident males make larger nests because they know they can defend it.
Similarly, a betta who has a tank all to himself is more likely to make a larger nest. A wild betta sharing a smaller space with many males is more likely to make a smaller nest.
Why Do Bettas Make Bubble Nests?
Male bettas create bubble nests to prepare for breeding.
They find an area of gentle, unmoving water with plenty of floating vegetation. They attach their bubbles to the plants and other floating debris. The floating items prevent the water from washing the bubbles away.
Once they’ve finished building their nest, male bettas look for females to mate with.
The Female Chooses Her Mate
As the males are building their nests, females swim around and choose a mate. They judge the quality of various nests, looking for one that indicates a suitable mate.
Usually, a female comes along while the male is finishing up his nest. He will wait under his nest and wait for a female to choose him if he happens to finish his nest without a mate.
Females don’t choose a mate based on the bubble nest alone. The male must also win her favor.
A male performs a complex courtship dance when he sees a female nearing his nest. He displays his bright, beautiful colors to try and win her over.
Eventually, the female will choose her ideal mate.
Spawning
Bettas spawn into the open water column. Females release their eggs, and males release their sperm.
Females become very still while laying their eggs, and often float on their sides in the middle of the water. The stillness of the female can be alarming to hobbyists who have never seen this before. Rest assured that it is completely normal.
Males usually wrap their bodies around their mate to help squeeze the eggs out.
Unfortunately, the males often squeeze their mates too hard. The pressure on their abdomens may cause internal damage. Many female bettas die after mating.
After the males fertilize the eggs, they collect them in their mouths and swim to the surface. They spit the eggs into the bubble nest.
The eggs remain safe inside the bubble nest until they are ready to hatch.
Caring For The Eggs
After spawning, the female leaves and does not bother with the eggs. The male stays behind and guards the bubble nest and his young until the fry begins to hatch.
The father is important in caring for the eggs. He will catch any eggs that fall out of the nest and place them back inside. He’ll drive off other female bettas wishing to eat the eggs. He’ll also drive away other hungry predators.
Leaving The Nest
Males remain near their nests until the young are old enough to emerge.
Unfortunately, males who do not have enough access to food may eat their own fry.
Making Another Nest
After the fry leave the nest, the male may begin to create another nest. Whether he chooses to make another nest depends on the season and his age.
The best time for male bettas to reproduce is between four and 12 months of age. They generally stop breeding by 14 months of age as their offspring may be less healthy.
Bubble Nests & Water Changes
Bettas may create bubble nests when there are sudden changes in water conditions. Wild bettas commonly make bubble nests with changes in temperature or rain patterns.
Bettas come from Southeast Asia where monsoons are common. Creating bubble nests is particularly common during monsoon season.
Captive bettas maintain this same bubble nest-making instinct.
Why Are Bubble Nests Good For Betta Fry?
Betta fish fry are tiny, weak swimmers. The fry hatches at the surface of the water. The surface tension of the bubbles creates a barrier. The barrier prevents the fry from falling into the bottom of the tank.
Remaining in the nest keeps fry safe from predators.
The bubble nest offers enough oxygen to help the fry survive.
Bettas live in stagnant or low-current habitats that are low in oxygen. Adult bettas are hardy and get enough oxygen by breathing at the surface. The fry are not able to survive in low oxygen conditions — the bubble nest keeps them oxygenated.
The bubble nest also provides the fry with a clean environment to live in. In the wild, the water may be muddy or silty, which is not good for betta fry.
Bettas Will Fight For Their Bubble Nests
In the wild, many bettas share the same vicinity. Although they inhabit nearby areas, they try to avoid each other as much as possible.
Bettas are “Siamese fighting fish.” They are territorial and won’t tolerate other bettas coming near their home or bubble nest.
Unfortunately for bettas, they are sometimes pushed together.
Bettas live in Southeast Asia, where the climate is hot and humid. They live in shallow rice paddies or puddles that don’t contain much water.
The heat causes the water to evaporate. The evaporation forces bettas closer together as their habitat disappears.
Bettas are fierce fighters who won’t hesitate to defend their bubble nest from other male bettas.
How To Encourage Your Betta To Make A Bubble Nest
Some aquarists wish to encourage their betta to create bubble nests. They may be planning to breed their betta, or they simply want to observe the behavior.
Either way, there are some things aquarists can do to encourage nest-building.
Low Flow
First, ensure the betta is living in a tank with little flow.
The water shouldn’t be stagnant because bettas need a filter to help keep their tank clean.
It is a myth that bettas don’t need filters. Plus, filters add oxygen to the water, which is essential in keeping the betta healthy.
Choose an adjustable filter when possible. These make it easy to decrease and direct the flow of the water.
A baffle may be necessary if the filter is still too strong. Baffles are anything that attaches to the filter to slow down the water. Many aquarists make baffles from sponges or plastic bottles.
Keep Floating Items In The Tank
Having items at the tank’s surface makes it easier for bettas to make their bubble nests. Floating pieces of driftwood, plants, or Indian almond leaves work well.
These are some of the best floating plants:
- Hornwort
- Elodea
- Crystalwort
- Red root floaters
- Water lettuce
- Duckweed (invasive & illegal in some places — check the area’s restrictions)
Feed A High-Protein Diet
Providing betta fish with a high-quality, high-protein diet encourages nest building.
Bettas should be receiving this kind of diet regardless. Still, it’s especially important for nest-building and breeding purposes.
Bettas spend a lot of energy creating their nests. They need an adequate diet to maintain that energy.
High-protein flakes or pellets are a good choice for bettas. Fluval’s Bug Bites are one of the best items to feed hungry bettas.
It’s helpful to give them snacks of live or frozen foods, too. Bettas go crazy for brine shrimp and bloodworms, and they should receive these foods a few times a week.
Don’t Touch The Nest
There is no need to ever touch a betta’s bubble nest. The nest does not harm anything and does not dirty the tank.
Touching the nest will only frustrate the betta because it will damage it and the fish will need to fix it.
How To Breed Betta Fish
Before breeding betta fish, set up the ideal tank for them. Their breeding tank should be different than the one they normally live in.
A tank that is about 10 gallons will be ideal. The depth of the water should only be about 5 in (12.7 cm).
Keep the tank in a quiet area without any distracting noise. Place lots of live plants inside the tank to give them places to hide.
Have something at the surface of the tank for the male to build his nest. A plant with a large, broad leaf or an Indian almond leaf is a great choice.
The water temperature should be 78-80°F (25.6-26.7°C).
Keep the lighting dim as bettas don’t feel safe spawning under bright light.
Keep the bottom of the tank bare — don’t use any substrates.
Keep the water flow low; it’s often better to forego a filter. Filters can damage the bubble nest and suck up the fry.
It’s vital to provide males and females with a high-protein diet before breeding. Spawning requires a lot of energy, and the mother and father must be in their best health.
Feed them more often than usual — about twice a day. A diet of daphnia, bloodworms, or tubifex worms is ideal.
They should begin this diet about two weeks before breeding.
Introducing The Bettas
Don’t introduce the male and female too early; they need time to get to know each other first.
Place a clear divider in the tank to cut the space in half. The male goes on one side of the tank and the female goes on the other. The divide prevents the fish from attacking each other while allowing them to get used to each other.
* Add the female to the tank first so she can explore the area without any stress. Add the male to his side of the tank shortly after. *
The male’s colors will darken and he will perform his courtship dance to entice the female.
The female’s colors will darken in response to him, and she will develop stripes.
Stripes that are vertical down her body indicate that she wants to mate. Horizontal stripes indicate stress and that she does not want to mate.
Adding The Pair To The Same Tank
The male will begin to create his nest and will finish it after about 12 to 24 hours. At this time, it’s safe to remove the divider and allow the male and female to interact.
Carefully observe the pair after removing the divider. Be prepared to separate the two if they display any aggression.
Generally, the female will head straight to the bubble nest. She will swim away or destroy the nest if she doesn’t like it.
Put the divider back up if the female doesn’t like the nest. The male will try to fix it to please her, after which the divider can be removed again.
The breeding pair is not compatible if the female rejects the bubble nest a second time.
Courtship
A happy female is one that stays near the nest. The male will begin his courtship dance, dancing and chasing her around the tank.
Such behavior is normal, although hobbyists should keep an eye on them. Some males become too feisty and may injure the female.
Both male and female will swim around each other, and they may flare at each other.
The courtship ritual may take up to three hours. Aquarists should leave the fish alone during this time.
Eventually, the pair will move closer to the nest. The male will flip the female over and wrap himself around her.
Spawning
Once the female is happy with the male and has developed her eggs, she will release them into the water column. The male then releases his sperm into the water column to fertilize the eggs.
Make sure to keep a close eye on the female. It’s often best to remove her from the tank after she releases her eggs.
Spawning can be very stressful for females. Sometimes, they feel compelled to eat their eggs because of that stress.
Gathering The Eggs
The male swims around, gathering the eggs in his mouth, and spits them into the bubble nest. The eggs collect in the bubble nest, where they will be safe during development.
Betta babies develop very quickly; it only takes two to three days to hatch.
Betta Fish Fry
The fry remains near the tank’s surface, protected by the bubble nest.
They may stay in their bubble nest for a few days to a few weeks after hatching. The fry won’t go to the rest of the tank until they can swim.
It’s best to remove the father from the tank once the fry begins to drop to the bottom of the tank. Males will sometimes eat their young if they don’t receive enough food.
Keeping the father well-fed is often enough to prevent this, though it’s better to not take the chance.
Feed the fry plenty of food — ensure the tank remains clean. The fry should eat infusoria, vinegar eels, or microworms. Once they get bigger, they can eat baby brine shrimp.
Begin separating the fry around two months of age. At this time, the fish begin to mature and develop their adult colors. They will start to become territorial and need their own homes.
Are There Other Fish That Make Bubble Nests?
Bubble nest building is rare, though it is not limited to bettas. Fish that make bubble nests usually live in stagnant, shallow, or muddy waters. The bubble nests help keep the fragile fry safe and healthy until they grow.
Most gouramis create nests from a mix of bubbles and floating plants. Gouramis are air-breathers with labyrinth organs like bettas. The two species are related, which is likely why they make similar nests.
Smaller gouramis species use mostly bubbles with only a bit of plant material. Larger gouramis, like giant and kissing gouramis, prefer plant material. They only produce a few bubbles to signal they are ready to mate.
Some larger members of the family Callichthyidae make bubble nests. One nest-builder from this family includes the Hoplo catfish (Megalechis thoracata).
What Other Kinds Of Nests Do Fish Make?
Cichlids are one of the biggest nest-builders in the aquarium industry.
Unlike bettas and gouramis, cichlids make their nests in the substrate.
They dig holes in the rocks or gravel of their habitat and lay their eggs inside. The eggs then stick to the hard surface of the stones.
Both male and female cichlids are great parents; they work together to protect their eggs. After laying the eggs, one of the parents watches over the eggs — usually the female.
Typically, the female fans the eggs to keep them oxygenated and debris-free. The male usually patrols the area to prevent predators or rivals from getting too close.
Cichlid parents even watch over their young after they hatch — something that most fish don’t do. The mother and father watch over their young and keep them safe from predators. The parents stick around until the fry are large enough to defend themselves.
FAQs
Do Female Bettas Make Bubble Nests?
Female bettas do not create bubble nests — that is the male’s job.
Unlike most animals, male bettas do more for the care of their young than females.
Yet, if a female takes an interest in a particular male, she may decide to pitch in. Females will not create an entire bubble nest on their own. Still, some will contribute to the construction.
Do All Bettas Make Bubble Nests?
The bettas we covered in this article were common bettas (Betta splendens).
Other betta species are mouthbrooders. They carry their developing eggs inside their mouths rather than in bubble nests.
The Brunei beauty betta fish (Betta macrostoma) is one of many betta species that mouth broods. Brunei beauties are rare in the aquarium hobby, though they are becoming more popular.
Do Bettas Make Bubble Nests When They’re Happy?
Many aquarists say that a betta making a bubble nest is a sign that they’re happy.
There may be some truth to this — bettas are unlikely to want to breed if their aquarium conditions are poor. A bubble nest may show that the aquarium is healthy and meets the betta’s needs.
Still, there is no evidence to show that bettas make bubble nests simply because they’re happy. The behavior stems from instinct and the drive to reproduce.
Does There Have To Be A Female For Males To Make A Nest?
There does not need to be a female nearby for a male to create a bubble nest. Many times, males will simply make bubble nests because they’re ready to breed and are being prepared.
Many hobbyists notice their males making bubble nests even when there are no females.
The nest will start to break apart after about one week of no use.
