Betta Fish Behavior 101: How to Keep Yours Happy & Healthy

happy betta fish
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Last Updated: July 16, 2023 by Flora Gibbins

When I brought home my first male betta fish, I was almost immediately surprised at how different they are psychology-wise from other fish. 

Even though betta’s body language signals are similar to other fish, the mentation behind it is often startlingly different.

Sadly, most “experts” on betta fish behavior or betta splendens psychology tend to misread these fish, and thus wrongly promote the idea that bettas are more aggressive and hostile than other fish that live in schools and shoals.

happy betta in tank


It only takes a few moments to realize that the lethargic fish sitting in an isolated tub at the pet store isn’t the same betta that comes to life once you put him or her in a new tank.

A betta fish actually needs a good-sized tank to properly get around in. A 5-gallon tank should be ideal, or you can check out some of our recommended betta fish tanks

Sadly, if you did even a small amount of reading on betta fish, you will always be thinking of them as “Siamese fighting fish”, and all the prejudices that go with that title.

Over the years, I have been increasingly saddened by the insistence of some “experts” that go on saying betta behavior is mostly about aggression, hostility, and violence.

Uncategorically speaking, betta fish don’t have much in the way of fin, tail, and body shape to give them such a fearsome reputation. 

While male bettas do show considerable aggression to each other, a fight can also take hours to end. 

By contrast, when they are up against smaller aquarium fish of other species, the betta itself is likely to be dead in under 15 minutes

It is my hope that when you take a second look at betta fish body language, you will also see the vast majority of information about their psychology couldn’t be further from the truth.

Gill Flaring

One of the first things I learned about betta fish body language is that gill flaring isn’t always about aggression.

Very often, I’ve had betta fish deliberately look at me sitting at my desk and flare for no reason. It didn’t take long for me to figure out my aquatic pet was signaling he wanted more food.

The key to understanding gill flaring is about understanding the betta fish wants to be noticed. That doesn’t mean normal betta fish behavior mainly focuses on scrapping for a fight.

I think the “logic” experts use to explain gill flaring as a form of aggression probably stems from observations of other animals. 

For example, dogs will bristle along the back of their neck and spine and cats will puff up their tail and body fur to signal intent to fight or attack.

This is distinctly different from bettas that will flare simply because they are curious.

Sometimes I think bettas will also flare to give a different kind of warning. Even though they are brightly colored creatures, they originate in water that is very murky and hard to see through.

As such, they may not always trust other creatures in the water to recognize the fact that they are present. 

You could say that gill flaring may be akin to your car’s tail lights going on when you hit the brakes. 

It’s not about aggression, it’s about making sure other drivers on the road have a specific understanding of what your vehicle is doing so that they can help avoid a collision.

Eye Placement Gives it Away

Together with gill flaring, it’s important to look at eye placement and visual acuity. 

Typically, predatory or aggressive creatures have a very strong binocular vision to the front. Prey creatures, like horses and rabbits, see better to their sides.

Consider that tiger barbs, angelfish, tetras, and many other tropical fish all have eyes that angle easily to create a sharp visual field in front of them. Bettas have no such acuity in the frontal visual field. 

If you observe when they eat, you will see what I’m talking about. When truly aggressive fish species go to take food, they will move their eyes so that they focus sharply on the front. 

A betta, by stark contrast, will flip his or her head to one side or the other to locate the food before moving to eat it. 

Color or Marking Flushing

Color marking and flushing is one place where male and female bettas actually do show aggression much like other fish. 

The interesting thing about this is bettas are already brightly colored. Unless you really stop and look at them, it is often difficult to see that they are actually signaling aggressive intent.

Usually, I look to their chin area to see if there is hostile intent. In cases where they are signaling aggression, this area will take on a brighter color. 

Most of the time, this area is whitish or paler in color than the rest of the fish’s body.

Signs of a Happy Betta Fish

How to Tell if Your Betta Fish is Happy -

Bettas are far more inclined to signal they are happy than looking to have a fight.  When looking for an answer to the question “Is my betta happy?”, you can use these signs to see if your betta is content and feeling loving:

Building Bubble Nests

The answer to the question “How do I know if my betta is happy?” differs in males vs females. Males will build bubble nests. This is a signal that he’s looking to take care of baby bettas. While he will fight to protect the nest, it also indicates a much stronger interest in mating and nurturing.


Waving Pectoral Fins

Happy betta fish will wave their pectoral fins at you as a form of greeting. This is distinctly different from the routine motion used as a part of swimming around the tank. When male and female bettas look at you and increase the motion of their pectoral fins, it has nothing to do with swimming and everything to do with communication. In this case, the fish is usually telling you he or she wants a snack. 

Nap Habits

When seeking an answer to the question “How to tell if betta is happy?”, look at where they nap.  Male and female bettas will sprawl out and take a nap on objects near the surface of the tank as opposed to the bottom of the tank. 

One of the cutest things you will ever see a betta do is sprawl out on a leaf couch or some other ornament and snooze away. 

As with other creatures, when male and female bettas are napping out in the open, they are most likely feeling safe and happy.

Indicators of Illness

When bettas are coming down with some type of illness, they will express that with body language that differs from healthy betta fish. Here are some things you will see:

Subtle Increase in Activity

Early on in the disease, there may be subtle increases inactivity. For example, a day or two before an ich outbreak, they may snap at the water more when consuming food.

Stays at the Bottom or Hide

Fish that are progressing along on the healthy betta fish vs unhealthy spectrum will also more regularly begin to stay at the bottom of the tank or hide. 

Bettas are similar to other fish in the sense that they might shiver in place and move their eyes more as they scan for threats.

Decreased Coloration

Bettas will almost always become very pale all over their body when they are not feeling well. 

This includes situations where they are drowning or their swim bladder can no longer compensate for water that is too deep. 

Even though bettas have gills instead of lungs, they are still partial air breathers. As with dolphins and whales, it is entirely possible bettas need to take in at least some air directly as opposed to relying solely on their gills.

Clamped Fins and Tail

This is probably one of the easiest to spot, even in a veiltail betta. When fish are not feeling good, they will keep their dorsal, ventral, and anal fins close to their body. 

In the case of bettas, their tails also won’t flare out as much when they are swimming. You should also check for the possibility of fin rot.


Signs of Mental and Emotional Distress

One of the saddest things I’ve ever seen is otherwise healthy betta fish driven to the point of madness by ignorant owners that believe mirror aggression is “play” and makes them happy.

When male bettas see another male betta, there is, in fact, an aggressive response. 

Unlike when in the presence of another male fish, the situation is never resolved. It should be obvious this is no reasonable or kind answer to the question “How to keep a betta fish happy?”

If there is one thing about nature, you could say it abhors unfinished business. Nature always demands progression and moving forward through a specific process to completion regardless of the outcome to the individuals involved.

Holding the betta in an aggressive pattern is unspeakably cruel and psychologically damaging. The fish never gets a chance to satisfy the urge to complete the interaction.

As a result, the betta will show signs of aggression all day long and not pay attention to anything else in the fish tank. 

Over time, the fish will descend into complete madness and abandon nest building or other normal activities.

“Kennel pace” is a term you can use to describe abnormal repetitive behaviors in emotionally or mentally traumatized animals. For example, a cat or dog will pace back and forth in front of a window rather than eat or engage in other activities 

At times the pacing may become very frantic. Even if the window is open, the animal may not seek to go through the opening.

This is the best way I can describe the swimming behavior in neurotic male bettas.

As you can see in this video, there is a distinct behavior difference when bettas interact with each other vs with their own mirror image.

You can also see that the answer to the question “how to tell if my betta is happy?” has a lot to do with the lack of repetitive or useless behavior when there is a natural stimulus present as opposed to a mirror.

Aside from erratic swimming, a distressed betta may also stop swimming or engaging in other activities. They may become fussy about food options or fail to greet you as usual.

If bettas are showing signs of reduced activity, don’t forget to check the water chemistry and temperature to rule that out as a factor.

Check out our comprehensive guide to learn about other aspects of Betta fish care.

Frequently Asked Questions

1. Do you believe bettas are sentient and respond with emotions to their owner?

Yes. If you spend even a short time with a betta, you will realize they exhibit a full range of emotional responses independent of purely physical needs. 

I’ve seen bettas get insulted and stop eating, get angry and sulk, and dance to music that makes them feel good.

2. Can a betta recover from mental illness?

It all depends on how long and deeply set in the psychosis is set in. For example, a male betta that is still swimming away from a mirror image and not going back is probably still ok mentally and emotionally. 

If he’s spending over half his time in front of the mirror and no longer building bubble nests, he may or may not recover. 

As long as he is eating, however, there is a chance he will live to a normal lifespan and eventually engage in healthier activities. 

3. How to Make a Betta Fish Happy?

The first thing is to make sure there are no mirroring surfaces in the betta fish tank. Even though female betta fish are less attracted to mirrors, this can still be a problem.

Next, make sure the water chemistry is always within optimal parameters. When fish are exposed to non-optimal water, they can get sick, which can lead to depression and other stress reactions. Chemical adjustment or a partial water change may help.

It is also very important to make sure your betta has adequate and species-appropriate mental stimulation. 

Moss balls, leaf hammocks, ring gyms, as well as other betta fish toys are all excellent things agile-minded bettas will enjoy having in their tanks. 

Depending on the fish’s personality and sound affinities, certain kinds of music may also contribute to the betta’s mental and emotional well-being.

healthy betta in tank


Betta fish psychology is as unique as their body shape. They are enigmatic creatures that can and should make you rethink current concepts related to animal sentience. 

Once you learn how to interact with bettas, you will be amazed at how little “experts” really know about their behavior and what it likely means.

51 thoughts on “Betta Fish Behavior 101: How to Keep Yours Happy & Healthy”

  1. I have recently bought two little girls and was told by the pet store that my 1.6 gal tank was sutiable for them it had a filter and light my bigger fish angel is very happy swims around all the time and follows us when we look at her but my little girl Rebecca seems to stay behind the filter all the time she comes out to eat and goes right back I have a cave for them a leaf fish bed and I also play with the floating mirror at least once a day and she is not near as active as angel what do I do …..

  2. I really enjoy this newsletter. It makes me feel that I’m doing things right. Tomorrow is the day I go to the fish store and bring home 2 male bettas. I’ve been working on my tank for weeks and it’s finally ready. I have a 15G with a black divider, with holes, so each betta will have 7 1/2G. There’s a HOB filter, glass top, heater, lights, substrate, plenty of live plants, driftwood they can hide underneath in, rocks, and each side also has a coconut hut. At least 2 little bettas will be liberated from those tiny bowls. They really do look sick, unhealthy and unhappy, but each time I’ve picked up a cup, they perk up and start swimming around. I don’t believe they are sick – I think they’re just bored out of their little minds because they don’t have anything to do and no space to do it in. Tomorrow, that’s all going to change for 2 of them. I can’t wait!!

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