Betta Fish Angry – 10 Reasons Why Your Betta Fish is Flaring

Some people think fish don’t have emotions or don’t know how to express themselves. But that’s not true. Like every living creature, betta fish have different personalities and feelings. They’ll be happy when they see food, comfortable when they feel safe, irritated when surrounded by unfriendly tank mates, and angry when they feel threatened.

But this isn’t the only time betta fish gets angry. Betta fish keepers understand when they see their fish gills flaring, they aren’t happy. Bettas live by seeing colors and feeling the vibrations around them. That’s how they identify you when you get to their tank with food.

If you want to notice when your betta is unhappy, this article will help you identify when your betta fish is showing signs of anger, what’s causing their change in mood, and what you can do to help calm them down.

Read on to learn more! 

Behavior of Angry Betta Fish

What does an angry betta fish look like? Bettas are exciting fish, and there’s never a dull day with them. If you’re keen enough, you’ll notice your betta communicates through their actions. When these fish are happy, you’ll see them actively swimming in the tank, hiding in the caves, and gobbling their food.

betta fish flaring

But you must learn how to interpret their actions when in a betta tank to ensure they’re alright and not in distress.

For example, if your betta fish is laying at the bottom of the tank, there could be several reasons causing this behavior. Your betta could be sick, tired, or pregnant. Monitoring their behavior as often as you can to help you identify the real cause behind their actions. 

Bettas are known to be aggressive fish, so their acting out is not new to aquarium hobbyists. You only have to identify what’s causing them to be angry and remedy the situation.

Below are some of the behaviors that indicate your betta fish is angry.

Betta Fish Flaring 

red betta fish flaring fins

An angry betta fish will be flaring. Flaring is when bettas’ gills flare up, spread their fins as wide as possible, and puff themselves up to look larger. When flaring, betta fish will also have a very sharp focus in one area of the tank. For other fish, betta flaring can be very intimidating and a signal they are ready for a fight.

Betta fish flaring in the wild is expected because, with numerous hiding spots, it didn’t always lead to a fight. But in captivity with limited space in a betta tank, likely, bettas won’t back down and a fight will break out. Fighting leads to injuries because fin nipping can be fatal to Siamese fighting fish.

Not all betta fish will flare their gills when they are angry. Some bettas could be flaring because of excitement, so you should be careful not to jump to conclusions. If your betta flares when you enter the room, or during feeding, there’s probably no reason to worry. Like humans, bettas have different personalities, so don’t expect all of them to behave the same.

Betta Fish Fighting 

When angry, some bettas will go to the extent of fighting. This can include swimming directly to other fish in the tank or nipping at their fins. If you’ve seen male betta fish fighting, they put their lips together and wrestle. These fights can lead to severe injuries.

Male betta fish fight to assert dominance in the fish tank, protect their food and shelter, or get access to female betta fish. You’ll have to monitor their behaviour to understand why they are fighting.

If you don’t see your betta fighting, you should look for other signs that a fight occurred. Check their body for missing scales or torn fins. If they are hiding more than usual, they could be trying to heal or avoiding the fish that caused the damage. 

10 Reasons Why Your Betta Fish is Flaring

Betta fish were given the nickname Siamese fighting fish for a reason. When necessary, these fish aren’t afraid to fight and get aggressive to protect their territory, food, and young ones from predators. But this isn’t the only reason these fish get angry. 

Below are some common  reasons why your betta fish could be angry and flaring: 

1. Stress

A lot of factors could be causing your betta fish stress, from the water temperature to the lack of swimming space or an illness. You’ll need to monitor your fish’s behavior, swimming pattern carefully, and eating habits to tell what’s causing the stress. It’s not uncommon for bettas to be angry when they are stressed. This anger can manifest in flaring because that’s how they communicate their feelings. The other reasons on this list can easily cause stress, leading your betta fish to act out.

2. Reflection 

Betta fish don’t like seeing their own reflections. Weird right? But bettas will respond aggressively to seeing their reflections. Whether it’s from a mirror or the tank glass itself, it’s easy for the reflection to cause them to flare and showcase aggressive behavior towards other tank mates. Your betta fish could also injure themselves by attacking their reflections in the mirror. If you have mirrors in the room where you keep your betta tank, ensure that it’s not directly in their view because they could mistake their own reflection for another betta fish coming to invade the territory.

3. Unfriendly Tank Mates

The fish you keep with your bettas are very important. The last thing you want is for a fight to break out in the tank or for your betta to bite at its new roommates. When bettas feel their territory is threatened, they act aggressively, and you’ll see them flaring. Male Bettas are mostly aggressive to other male fish, but you can keep them in a tank with female betta fish and other freshwater species. This betta fish care guide lists some of the best species you can consider as betta tank mates, like clown plecos, ember tetras, ghost shrimp, and Cory catfish. There’s also a list of freshwater species to avoid keeping in a betta tank. 

4. Lack of Swimming Space 

Bettas love their space. They need room to swim and explore the tank to feel comfortable. They grow to a maximum size of 4 inches which is bigger than most freshwater fish species. For this reason, they don’t appreciate being kept in a bowl or small fish tank for the entirety of their lifespan. The best betta fish tank size shouldn’t be less than 5 gallons. This is only the minimum; if you want them to be happy, go for a 10-15 gallon fish tank. They will become aggressive and angry if they feel too confined by their space. 

5. Diseases

Betta fish are susceptible to various illnesses because of their sensitivity to their environment. These illnesses, if left untreated, can cause death, especially swim bladder disease in bettasStress affects your betta’s immune system allowing the bacteria that live in the tank a chance to attack your betta and make them sick. When bettas are sick, they won’t be their usual active selves; they will hide, lie on the bottom of the tank, or become aggressive towards other tank mates. 

6. Boredom

Yes. As unbelievable as it sounds, betta fish can get bored without any entertainment or stimulation from their surrounding. Most Aquarists understand this. That’s why they ensure that the fish tank has decorations like driftwood, caves, and plants to keep your freshwater fish interested in their environment. To keep them happy, you must ensure their tank is similar to their natural environment. The lack of stimulation can easily lead to aggressive behavior like flaring.

7. Poor Water parameters

Maintaining the proper water parameters is crucial for these fish because any drastic changes can cause stress or severe health issues. The ideal water temperature for bettas is between 78-82 degrees Fahrenheit because tropical creatures require their water to be warm, but not too warm because this can make them angry and cause flaring. Cold water will also slow down their activity and metabolism. The Best water for betta fish is betta-specific water because it doesn’t contain harmful chemicals and is best suited for their needs.

8. Feeding them the wrong food 

Betta fish are very sensitive. Especially what they eat; you can’t just feed them old leftovers and think they’ll grow healthy and happy. They’ll be unhappy, and you will notice their change in mood. Your betta won’t be as excited to see you or swim to the water’s surface when you drop in food. A hungry betta will also show signs of aggression. If you’re struggling to find the best food for your betta fish, a feeding guide will help you choose the best food and how often to feed betta fish

9. Breeding

They could be flaring if it’s the beginning of the breeding period. Female and male bettas breeding is fascinating to watch. When you introduce a male and female betta for breeding, the male betta will want to impress the female betta. They will do this by flaring to expose their beautiful fins and body to convince the female to mate. The female will also flare in response to the male’s action, and this display can go on for days. If you suspect your fish is carrying eggs, there are various signs you will see to tell if your betta fish is pregnant

10. Excitement

Your betta flaring isn’t always a bad thing. They could be doing this because they are happy. Some aquarists have noticed their bettas flaring in the morning when they see food. They move around the tank showcasing their fins, moments before the food hits the water. If your betta is flaring because of this, then you are raising them the right way.

Is flaring good for bettas? 

Yes, it is sometimes. Flaring isn’t completely bad for these fish. In fact, don’t be surprised if you find your betta flaring during the day. Bettas could be flaring because they need to stretch their muscles after swimming all day. It could also be a way for them to relax.

But you’ll need to check for other symptoms like fin rot to ensure that their only flaring is to stretch and relax their muscles. A combination of other symptoms could indicate illness or unhappiness with their environment.

If your Betta fish isn’t flaring, you can help them by putting a mirror outside their tank, and you’ll see them flare. Do not put the mirror inside the tank because this can cause your betta to flare too much, which is harmful to their well-being.

How to Keep Your Betta Fish Happy and Healthy

If you notice your betta fish showing signs of aggression, don’t worry, there are several things you can do to cool them down and reduce their anger. The most important thing any betta fish keeper should consider is what triggered their aggressive behavior. Once you know this, it will be easier to keep them happy and healthy using the methods listed below:

1. Do not keep male bettas together

It’s evident by now to any aquarist that male betta fish do not want to be in the same tank. Keeping two male bettas will only lead to fights and aggressive behavior like flaring. No matter how large the tank is, one of your male bettas will start flaring if they feel that territory is being invaded.

2. Keep them with friendly tank mates

Just because you can’t keep male bettas together doesn’t mean your fish should live alone. Bettas don’t like fish that are brightly colored or larger than them. They will feel threatened and possibly act aggressively during their time together. 

3. Place your betta in a spacious tank

Bettas aren’t only beautiful; they are also very active fish who like to swim around their tank and explore their environment. Having enough space to swim will keep them calm and happy without worrying about another species in their space.

4. Increase the hiding spaces

There are several reasons why your Betta fish could be hiding, but one of the main ones is they simply like doing it. Bettas hide to feel safer and less threatened by their surroundings, especially in a community tank or a new fish tank. With more hiding spaces like rocks, caves, and floating aquatic plants, they can relax better and reduce their stress.

5. Ensure their environment is stable

Bettas are very sensitive freshwater fish. That’s why any drastic changes in the water parameters or their environment can cause stress or lead to illnesses. As a Betta fish keeper, you need to ensure their living environment is stable to avoid any acts of aggression. This includes everything from the ammonia and nitrate levels to the pH and temperature of their living environment.

6. Keep them on a healthy diet

Like other creatures, bettas need certain nutrients to grow healthy and happy. Without a nutritious diet, your betta could start acting out and causing problems you’ll have to deal with. When angry, some bettas will even avoid eating. A lousy diet could be one of the reasons your betta fish isn’t eating. And fasting for more than a week isn’t healthy for these freshwater fish. 

7. Reduce the reflection in their tank

One of the main reasons why your Betta fish might be flaring is because they keep seeing their reflection. You have to ensure that there are no mirrors around the tank in the location where you place them. For them, seeing their reflection is like seeing another fish/male betta fish coming to claim their territory.

8. Change the lighting in the tank

Some fish need light at night, but poor lighting in the tank can cause your betta to see their reflection and end up attacking it. Changing the aquarium lighting can stop this and reduce the aggressive behavior in your freshwater fish. 

If you didn’t change the aquarium lighting, the next best option would be to move the fish tank to a new location. If none of these work, try covering the sides of the tank but ensure you leave one side open because these freshwater fish need light during the day.


Is flaring bad for bettas? 

Now that you know about the nature of these fish, flaring in bettas is normal. So don’t always assume something is wrong when your betta does this. This normal behavior asserts dominance in their environment, but too much flaring can harm your freshwater fish. It can lead to stress or weaken their immune system, exposing them to various illnesses.

Do female bettas flare? 

Yes. Although the female Betta fish aren’t as aggressive as their male counterparts, they might still flare when they encounter their reflection in the tank. Or when breeding with male bettas.

Why is my betta fish not flaring? 

Betta fish not flaring isn’t a cause of concern. These fish have different personalities; some might only flare when they’re stressed or feel threatened by other fish.


While you might want to help your betta be calmer and less aggressive, you must accept that some of these species will be naturally more aggressive. If all these tips aren’t working, your betta might want permanent personal space. And there’s nothing wrong with that.

But if your betta fish is flaring too much, something is wrong. You want your betta to be healthy and happy while in your care. Tips like keeping them in a more spacious tank, adding more hiding spaces, and giving them enough food will help them stay calmer and reduce aggressive behavior.

If you are still uncertain of what’s causing your betta to act out, you can add toys and other tank decorations to help distract them. Although bettas are known to be hardy fish, you’ll have to be intentional about their environment to keep them relaxed.

Leave a Comment