betta fish siamese fighting

How Do Betta Fish Fight: Top Signs Of Aggression

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For a fish named after the art of fighting, you might be wondering to yourself how exactly the Siamese fighting fish (Betta splendens) engages in combat. These fish should never be purchased with the intent to have them fight, but it is important to know signs of aggression, especially if placing your betta in a community tank setting.

Keep reading to find out everything you need to know about betta fish fighting, signs to look out for, and how to stop your betta from fighting in your own tank!

The history of betta fish

In order to understand the behaviors of your betta fish within your aquarium, you need to first understand their origins.

Over 150 years ago, it is believed that wild betta fish were collected from their natural environments in slow-moving, small bodies of water throughout Thailand (formerly known as Siam) and Malaysia. Due to the natural aggressive tendencies of these fish, bettas were eventually used to fight for monetary gain and bred to further express this aggression; male bettas were especially coveted for their intense colors and enhanced fighting style.

Even the then-king of Siam, Rama III, participated in these events and began requiring licenses to own and fight the species. Some of the king’s most prized bettas were given to a scientist, Theodore Edward Cantor, that originally identified them as Macropodus pugnax. Due to overlapping names, the species was soon reassigned by Charles Tate Regan as Betta splendens.

The Betta splendens commonly sold today in pet shops are the result of decades of selective-breeding for color, finnage, and aggression.

How do you know if your betta fish is fighting?

Luckily, it is pretty easy to tell when your betta fish is engaging in a fight; hopefully, you will never have to see it though!

Male betta fish tend to be more aggressive than female betta fish and will set up territories that they defend with their lives. When another male betta is introduced into the tank, the original male betta will first start by displaying warning signs. These warnings signs include flaring their gills and spreading out their fins; this is in an attempt to make themselves look like a more serious threat and to give the other betta a chance to leave before a fight ensues.

However, these displays may also be made in response to another stimulus. Male bettas might prepare themselves for a fight if they feel threatened during feeding times or when protecting a nest. It is also believed that betta fish are more threatened by brighter-colored fish, which means that especially vibrant male bettas will almost certainly fight.

If the threat does not leave, these warning signs will soon turn into physical violence in the form of fin nipping. If you start to notice chunks of fin missing from one of your fish, red marks across their body, or if the fish has a sudden change in behavior, it might have been in a fight with your betta.

It is important to note that both male and female bettas flare their gills and will fight if threatened; some hobbyists have described their female bettas as being even more aggressive than their males sometimes!

Do male betta fish fight with females?

It is a common misconception that female betta fish are less aggressive than male betta fish. While they may not be as aggressive as their male counterparts most of the time, they are still not compatible with other females or males.

Male bettas are designed to fight and may not be able to distinguish a female counterpart from a threat. These male and female pairings often result in fights and subsequent deaths. Even during spawning periods, the male might harass the female to the extent of physical exhaustion and/or disease.

In general, male and female bettas should only be temporarily housed together when both are willing to breed and spawn; they should be immediately separated afterward to prevent possible aggression.

How do betta fish kill each other?

Betta fish kill each other and other fish by attacking their fins and inflicting open wounds. These open wounds can quickly lead to infection and/or exhaustion. These fights can last for considerable amounts of time, and usually, at least one fish will have died by the time the fight finishes.

If you’re lucky enough to catch signs of aggression before a full-on fight starts, the best thing to do is separate the two fish. It is not recommended to try keeping the two fish together again.

How do you stop your betta fish from fighting other fish?

Simply put, there is no way to stop your betta fish from fighting other fish. Some bettas are less aggressive than others and can successfully be kept with an assortment of tank mates; other bettas can’t even be safely kept with snails or shrimp.

However, if you notice that your betta fish is flaring in a tank of its own for unknown reasons, there are ways to diffuse its aggression; this is an important behavior to keep track of as over-flaring can lead to irritation and infection. One of the reasons your betta might be flaring with no apparent cause is stress. Stress could be the result of a recent change in scenery, water parameters, or livestock.

Scenery. When transporting a betta from one tank to another, your fish undergoes an incredible amount of stress; they have been removed from their comfort zone and placed into a new surrounding where everything is new. If you notice that your new betta is flaring for unknown reasons, it may be safe to assume that it is due to this transitory period. Some hobbyists have also experienced their bettas flaring up at their own reflections on the glass. This behavior should subside within a couple of weeks. However, make sure that your betta isn’t exhausting itself and/or bringing physical harm to itself.

Water parameters. A change in water parameters could also make your betta stress out. Important parameters to watch out for are ammonia, nitrite, pH, and water temperature; nitrate is also important, but only really becomes a concern at extreme levels. Stability is key for bettas, and any sudden swings could make your fish act out of character! If your betta begins to flare, make sure to check water conditions and adjust accordingly.

Livestock. If you think that you have an especially docile betta that you think would do well in a community tank, the transition might still be rough. As we mentioned before, these fish are extremely protective of their territories, and transporting them out of their comfort zone can cause a little confusion and subsequent aggression. During this time, it might be normal to see your betta flaring every once in a while. However, make sure that this behavior does not persist and that there is no fighting. Remember, even though your betta fish might have seemed unproblematic on its own, there is no way to predict how it will act in a community tank setting.

All in all, there is no way to stop your betta fish from fighting; Siamese fighting fish were bred to fight. As long as you pay attention to the signs that your fish is giving you and stock with a plan ahead of time, you should have little to no problems.

Top betta fish tank mates

If you’re thinking about trying to keep other livestock with your betta fish, it is best to pick out the ones that have proven to be successful for most other hobbyists. Keep in mind that in order to keep betta fish with other fish tank mates, it is preferred to start out with at least a 15 gallon (56.8 L) aquarium.

Here are some of our top betta fish tank mates:

Snails. Snails are always a good option for any fish tank; they clean the glass and substrate, have colorful shells, and bring some extra excitement to the tank. While they might not be as exciting as a school of tropical tetras, there is little to no chance of your betta fish fighting your snail; though if you have an especially hungry and/or aggressive betta, there are definitely stories of snails becoming quick betta snacks!

Shrimp. Shrimp as also a good betta fish tank mate, though they are even more likely to get eaten than snails. As long as you go with larger species, you shouldn’t have too many problems though. Shrimp can add lots of color to the tank and help clean up the waste and detritus from your betta.

Corydoras. If you have a 20 gallon (75.7 L) aquarium or more, you may be able to house Corydoras catfish with your betta. A school of 7 or more pygmy cories (Corydoras pygmaeus) is always a favorite for betta fish tanks; however, these fish can be pretty active and often venture up into the middle water column. This could lead to potential fighting between the two species, though an appropriately sized tank and school of pygmies should help lessen aggression.

There is a lot of discussion about whether or not females bettas can be kept with each other in groups known as harems or sororities. In general, we find that harems are unsuccessful more times than not and do not recommend ever putting more than one male betta or one female together in the same tank.


betta fish fighting in an aquarium

Betta fish have been bred over the decades to express the most beautiful colors and aggressive behaviors, earning them their name of Siamese fighting fish. There are a few ways to tell when your betta fish is about to fight, but as a responsible fish owner, you should never let it get to that point. However, if you find that your betta is flaring its gills and fins for no apparent reason, this behavior might be due to stress, like changes in scenery, water parameters, or livestock.

If you have any questions about aggression levels of male or female betta fish, or have had experience dealing with a particularly grumpy betta, don’t hesitate to leave a comment below!

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