Can a Betta Fish Drown?

Can a Betta Fish Drown?

A fish drowning? That seems like an absurd idea, but the theory that bettas drown in large tanks has been circulated. It’s something quite often said and heard, but is it true?

Betta fish, just like every other fish, can drown if the right (well, wrong) circumstances present themselves. All fish need oxygen to live, and if something interferes with their ability to get that oxygen, they will drown. Betta fish are actually less likely to drown than other fish due to their labyrinth organ. A betta fish is less likely to drown in a large tank than, say, a cichlid.

In this article, we will discuss the natural habitat of betta, large tanks, ammonia and nitrite poisoning, trapped fish, the labyrinth organ, and swimming strength.

Natural Habitat

A widely circulated rumor is that bettas live in small, dirty puddles. This could not be further from the truth. The natural habitat of the betta is massive, many miles wide, and extremely clean.

This falsity likely came about because someone did see bettas in puddles. In some areas of the world, including the ones that bettas come from, there is a wet season and a dry season, instead of four distinct seasons.

During the dry season, some bodies of water dry up and trap bettas in small puddles. People then see these small puddles with bettas and assume they live there. Unfortunately, the bettas often die a short time later.

In addition, the tannin-rich water looks unclean to most, despite it being extremely clean and healthier than most water. Tannin-rich water appears tea colored and is known as Blackwater. The tannic acid leaches from plant matter falling in the water and turns the water from clear to brown.

While brown water may look extremely dirty, the tannins are actually very beneficial to fish. Tannins have both antibacterial and antifungal properties, so they help fish fight off low-grade infections and help keep the eggs from getting fungus, though most bettas can do this themselves.

Large Tanks

Because of the puddle myth, some assume that bettas can only live in shallow water, or else they would drown. This is not a logical statement, as betta fish are, well, fish. Fish have gills; they breathe dissolved oxygen from the water.

In recent times, a betta’s habitat has become shallower. Population expansion and deforestation have diminished the area that bettas can live in, so they have started to move to other areas.

One of the most popular areas that bettas have moved to are rice fields. These fields are not very deep, often only an inch or two, to facilitate planting and harvesting. Bettas can inhabit these areas as they are rich in bugs, warm, and still.

Some domesticated bettas do have long fins that inhibit their swimming, but the easiest way to remedy this is to simply have decorations between the substrate and surface that they can rest on. Even without decorations, the deepest commonly available aquarium is only 29”, and they will still be able to swim this distance.

Even if they cannot swim this distance, they still have gills. The only way they would drown would be the same way as other fish.

Ammonia and Nitrite Poisoning

These types of poisoning are unfortunately very common and do lead to the fish drowning. Ammonia is the first stage of the nitrogen cycle in aquariums, and nitrite is the second.

Bettas are typically a starter tropical fish, as they are relatively easy to care for and hardy. All they need is a 5 gallon tank, two types of main food and one supplementary food, a heater, a filter, and that’s it. However, since they are a starter fish, new owners often subject them to fish-in cycles.

Ammonia is extremely toxic to fish and causes severe burns. The burns often cause serious damage to the gills and prevent the fish from breathing properly, or at all. The damage can become severe enough that the fish will be unable to breathe and will drown.

Nitrite binds to hemoglobin in the blood and prevents it from carrying oxygen. Like all animals, fish need to circulate oxygen through their blood in order to survive, and if they cannot do this, they will drown.

Ammonia and nitrite are present in uncycled tanks, and it takes around one month to cycle a tank properly. Unfortunately, the nitrogen cycle is not common knowledge among betta keepers, and most either get a betta and add it to the tank immediately, “cycle” the water for 24 hours, or set up the tank and leave it for a month.

While bettas can survive a fish-in cycle, ammonia and nitrite must remain at or below 0.25ppm, which requires water changes daily or every other day. Leaving water in a tank for 24 hours often removes chlorine but does not do anything for the actual cycle.

Setting up and leaving the tank for a month also does nothing, as there is no ammonia source, meaning the cycle never starts.

Trapped Fish

As you may know, fish must continuously move in the water to force water to flow over their gills. Without their forward movement, water will not move through the gills, and the fish cannot extract dissolved oxygen from the water.
For example, most sharks caught for their fish drown. After fishermen catch them, their fins are sliced off, then they are returned to the water. Since they are entirely unable to swim whatsoever, they sink to the bottom of the ocean and drown after several hours.

While fish in aquariums do not often experience losing all their fins, they can become trapped by decorations. Sometimes they get stuck inside of decorations and are unable to get back out, other times they get trapped under the decoration or between the decoration and something else.

While they can survive trapped for several hours, there is a good chance of them dying soon after this time. They can die sooner, especially if they get trapped inside of a decoration, because there is little to no water flow in those areas.

They often have a better chance of survival if they are trapped between the decoration and the glass, or between two decorations. There is still water flow here, and sometimes it is enough to keep them alive for days.

Labyrinth Organ

Betta fish are actually less likely to drown in instances of poisoning than other fish. This is due to a specialized organ they have developed. The natural habitat of the betta is very warm and normally stagnant water, which means there is very, very little dissolved oxygen.

In order to survive in this difficult environment, the betta, and other labyrinth fish, evolved a labyrinth organ, which is similar to a basic lung. This organ allows bettas to breathe atmospheric air and extract oxygen from it.

Essentially, this means that bettas do not need to entirely depend on their gills. Therefore, if they suffer severe gill damage from ammonia and/or nitrite poisoning, they have a much better chance of surviving than other fish, as they can still breathe.

That being said, if the damage is severe enough to kill the gill tissue, the fish will pass. In addition, if a betta cannot use their labyrinth organ, either from a film on the surface or not having access to the top of the tank and the atmosphere, they will drown in this situation as well.

Swimming Strength

The primary reason that bettas could potentially drown (aside from becoming trapped) is their long fins. While not all varieties of bettas have long fins, such as plakats or wilds, the majority of those sold in local stores do have excessive finnage.

Not only do the long fins make it more likely for the fish to develop fin rot, it is also more likely that they will have swimming issues. The betta did not evolve with long fins; that was a selectively bred trait. Unfortunately, their little bodies cannot handle these long fins, so they often have difficulty swimming.

While it is rare, it is possible for bettas to grow fins so long that they cannot swim. In these cases, cosmetic surgery is required. The fish is sedated, the fins and instruments are sterilized, and parts of the fins are cut off.

This is an extremely rare occurrence, so this surgery is not often available. When the rays, or bones in the fins, break or are cut, it is unlikely for the fin to grow back past that point, but this too is possible.


Betta fish are not more likely to drown than other fish. All fish can drown, and bettas are actually more likely to survive severe gill damage than other fish. The only disadvantage they possess is their long fins, but most of the time the fins do not interfere with a betta’s ability to survive in aquariums.

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