Originally found in the central plain of Thailand, betta fish are among the oldest domesticated fish species in the world, having been owned as pets for more than 1,000 years.
Their beautiful fins and vibrant colors are amazing enough on their own, but there is an interesting question about this species that you might not even have thought about asking yourself: how do betta fish breathe?
This article will answer this question and many more to help you to understand how the fascinating betta fish has adapted to breathe in a way that few other fish can.
How Do Betta Fish Breathe?
Just like any other animal, fish need oxygen to survive. Most fish species obtain the oxygen that their bodies need through the use of gills, which allows them to essentially breathe underwater. Water passes through their mouths and across their gills, where oxygen is absorbed directly into the bloodstream, from the water, via capillaries.
However, not all fish breathe in the same way. Betta fish, otherwise known as Siamese fighting fish, have adapted to be able to take oxygen from the air at the surface, as well as absorb oxygen while they are underwater. If you are lucky enough to raise some of these beautiful fish, you will probably have noticed them gulping air and breathing with their mouths out of the water.
Bettas are part of a subgroup of fish that all have this incredible ability, and they are known as “anabantoids” or “labyrinth fish.” These fish species have a specially adapted organ that is similar to a lung, known as a “labyrinth organ,” which allows them to absorb some oxygen from surface air to fulfill their needs when they are not getting enough.
Why Do Betta Fish Breathe Air?
If you notice a betta fish coming up for air, it means that they are taking a breath to get in a bit of extra oxygen. Most fish species are able to get all of the oxygen that they need directly from the water in which they live, using their gills, but some have had to develop other ways to take on oxygen and adapt to challenging habitats.
In the wild, betta fish live in water that is very low in oxygen, so there is not enough around for them to survive through the use of gills alone. The ability to breathe air by rising to the surface allows them to live in these difficult waters where other fish would simply die from a lack of oxygen.
As with most labyrinth fish, breathing air is one of the primary ways that betta fish get the oxygen they need and rely on it for survival. Because they are adapted to low-oxygen environments, they don’t absorb as much oxygen from the water around them. They need to supplement it by breathing surface air, even when they are living in oxygen-rich water.
Do Betta Fish Breathe Through Gills?
Despite the fact that they are able to breathe air without using their gills, betta fish do still breathe through their gills as well. Having a labyrinth organ that lets them breathe surface air is simply an additional source of oxygen for all labyrinth fish, not the only method they can rely on.
In fact, one of the defining characteristics that make a fish a fish is the fact that they have gills, so all fish species have them, and they all use them to breathe when they are underwater. In oxygen-depleted waters, fish adapt and find other ways to get oxygen into their bloodstreams as well, but they all still breathe through their gills.
The main difference between the gills of a betta fish and those of other species is that they are not as efficient because bettas don’t rely solely on them for their breathing needs. Bettas may not get all of their oxygen through their gills, but they certainly use them and are actually much happier when they are in waters with higher oxygen levels.
What Is a Labyrinth Organ?
So, what exactly is this strange and rather wonderful labyrinth organ? It is not quite a lung, but you can think of it as quite similar to one in the way that it functions. It is actually an extension of the gill plates, which are the bones that keep the gills in place, and it is made up of many folds of bone.
The labyrinth organ is formed through a process known as “vascularised expansion”, which essentially means that it grows and develops as a result of significant blood pressure. This vascularised expansion forms the complicated bone folds that make up the majority of the organ and covers them in lots of very small blood vessels.
When air enters the central chamber of the labyrinth organ, it interacts with the blood vessels that run over every fold of bone, allowing oxygen to be extracted directly into the bloodstream. This is actually very similar to how lungs function in mammals, though the structure and formation of the labyrinth organ are ultimately very different.
How Do Betta Fish Use the Labyrinth Organ?
Betta fish use their labyrinth organ to breathe oxygen directly from the air. They will swim up to the surface and take a big gulp, filling the chamber within their labyrinth organ and allowing oxygen to be taken directly into the bloodstream.
Bettas breathe air using their labyrinth organ throughout the day and during the night, but they like to sleep in the shade underneath some sort of vegetation. Because of this, they prefer to sleep under large plants near the surface of the water so that they don’t have to exert lots of energy in order to get to the top when they need a quick gulp.
Another interesting use of the labyrinth organ is in the creation of intricate networks of bubbles at the surface known as “bubble nests.” Betta males blow bubbles to form one of these nests as part of their reproductive process, but even single males without a female companion will make a bubble nest if they are comfortable and content in their space.
Do Betta Fish Need to Surface for Air?
There are two types of labyrinth fish that can breathe air at the surface, and they are known as facultative air breathers and obligate air breathers. Facultative air breathers only breathe at the surface when they are running low on oxygen in the water around them, so they don’t always use their labyrinth organs when they are in oxygen-rich water.
Obligate air breathers, on the other hand, need to take on oxygen from the air in order to survive, so surfacing to use their labyrinth organ is essential. Betta fish fall into this category, and they cannot live without occasionally taking a few breaths of fresh air.
This means that these fish need to be able to reach the surface, and they need a good amount of air from which to breathe, even when they are living in a tank or in water with high levels of oxygen. Bettas are much healthier in oxygen-rich waters, despite the fact that they can survive under harsher conditions, but they always need to breathe at the surface.
Is My Betta Gasping for Air?
If you are noticing your betta fish coming to the surface too often and taking what looks like desperate gulps for air, it may be a sign that they are running low on oxygen. Although breathing at the surface is a natural and necessary process for bettas, they can start gasping for air in a more frantic manner when they are not comfortable in their environment.
Although they are very hardy, betta fish can become starved of oxygen and suffer as a result. If you notice that they are taking much larger mouthfuls of air than usual and needing them more frequently, they may be struggling in their tank. You might also see their gills opening wider while they are breathing underwater.
You want your betta fish to be as happy and healthy as possible, so they should be living in waters that are oxygen-rich, temperature-controlled, and regularly cleaned. If your betta fish is gasping for air, it probably means that they are struggling to get oxygen from the water, which may mean that it is oxygen-deficient, it is too warm, or it is too high in ammonia.
FAQ
Do I Need Extra Oxygen in My Tank?
Betta fish can generally survive without having any extra oxygen added to their tanks, but that doesn’t mean that an air pump wouldn’t be beneficial for their health. Adding extra oxygen to the water in your tank can make your bettas much happier and healthier, but clean, warm water that is changed regularly will usually be enough for their needs.
What Fish Are Labyrinth Fish?
There are many different fish species that are classified as labyrinth fish, meaning that they fall within the suborder “anabantoidei.” Besides the bettas, you can actually find many of them for sale in pet shops. All of the gourami species are labyrinth fish (including blue gourami, chocolate gourami, dwarf gourami, and many more), and paradise fish are anabantoids too.
Recap: How Do Betta Fish Breathe?
Bettas are part of a subgroup of fish known as anabantoids, which have developed a fascinating organ to allow them to breathe surface air in order to take on more oxygen than they can get from the water around them. This organ is known as the “labyrinth organ,” and it functions like a lung, allowing oxygen to be absorbed into the bloodstream directly from the air.
To use their labyrinth organ, bettas regularly swim up to the surface and gulp down some fresh air. Betta fish also use their gills to take on oxygen while they are underwater, but they are not very efficient, so bettas don’t get as much oxygen from the water as other fish. Betta fish are obligate breathers which means that they have to breathe surface air to survive.
Bettas are very popular fish to keep as pets, and they have been for at least 1000 years, in part because they are hardy and able to live under harsh conditions. Although this is the case, bettas are much happier and healthier in oxygen-rich waters where their needs are properly met, so they don’t need to gasp for air or struggle to survive.
Breathing oxygen directly from the air is a fascinating and quite unique skill that not many fish possess. The beautiful and elegant betta fish is very special in this and many other ways, and they make for wonderful, lively pets.