Why Do Betta Fish Flare Their Gills?

Bettas are some of the smartest fish you can keep as a pet. They are responsive, quirky, and quick to learn different behaviors.

You will sometimes find your Betta fish chilling on the substrate in the water tank or swimming around from corner to corner.

However, there may be a time there you might find your Betta fish aggressively flaring its gills.

So, what does it mean when a Betta fish aggressively flairs its gills? Is it friendly behavior? Do only male Bettas do it? Should you be concerned?

When you buy a new Betta fish for your fish tank, it is possible that it flares its gills in the beginning.

This can be confusing, especially for a new fish owner.

Let’s explore the reasons why a Betta fish might flare its gills:

Possibly an Act of Claiming Territory

By nature, Betta fish are incredibly territorial species.

Due to this tendency, two Betta fish may flair their gills when they come across each other.

This is an act of claiming territory. This is why two male Betta fish cannot live peacefully in the same fish tank.

They flare their gills because they automatically consider the other Betta fish as an intruder.

Due to their temperament, they do not prefer other male Betta fish entering their territory; hence, the display of gills (like a show of strength to keep the other one in limits).

Male Betta fish do not get along

If a male Betta fish spots another male Betta fish, the automatic response is to puff out its gills to appear wider.

This makes them appear twice as big in hopes of intimidating the fish that entered their territory.

It is not necessary that male Betta fish flare their gills at other Betta fish only. They could display this behavior with any other aggressive fish that might be in their tank.

This is also a possible reaction to anything they are scared of or even a human passing by.

Betta are Territorial by nature

Betta fish display territorial aggression because that is how they have lived for centuries in their natural habitat.

This particular fish species does not hesitate to display violent behavior towards any intruder that enters their territory.

Betta fish are typically more threatened if the trespasser displays the same or more amount of aggression towards them.

As an automatic response, they will try to match their competitor’s aggression level by flaring their gills.

In a wild setting such as a pond, Betta fish flare their gills at each other pretty regularly if they feel that someone has intruded into their territory.

However, this goes on for a while till one of the aggressive parties eventually backs off.

When it comes to fish tanks in our homes, it is wise not to place male Betta fish together unless they have a substantial amount of space.

Remember, each mature Betta fish need at least four to five gallons of water to be happy.

Being in fish tanks gives them a limited space, with very few hiding places. This makes them more insecure than if they were in the wild.

As a result, they end up fighting more and also causing each other injuries.

Therefore, if you want to place two male Betta fish in a single fish tank, it should be at least a minimum of 8-10 gallons (bigger would be better).

This allows them to live in peace by forming their territories.

In terms of gender, a male Betta fish can flare its gills at another male or even a female intruder.

However, most issues happen between male Betta fish.

In some cases, you may notice Betta fish refusing to eat if the presence of a trespasser stresses them.

This leads to multiple health and stress-related issues for them.

Your Role as a Fish Owner

As a fish owner, you should choose your Betta Fish’s tank mates carefully.

You should also decorate the fish tank with live plants, rocks, and other decor pieces to give them several hiding places.

Just a few efforts on your part will give your Betta fish the personal space that it needs in order to be happy.

It will keep them stress-free and reduce aggressive behavior.

However, there may be some cases in which your Betta fish has extra temper issues.

Regardless of your efforts, you may not be able to stop it from behaving aggressively.

In that case, you should consider giving your pet a separate tank, so it does not bother the other fish.

Glass Reflections Can Be the Cause

If you notice your Betta fish flaring its gills even when it is the only fish in the tank, it is either flaring them at you or its own reflection in the glass.

It is very likely for a Betta fish to be intimidated or aggressive towards its own reflection.

Since they do not understand the concept of mirror reflections, they perceive their own reflections as an intruder in their territory.

If you find your fish in a similar predicament, you can add a few more plants in the tank to avoid your Betta fish seeing any reflection that may stress it out.

Another great thing to do is add floating lights to your fish tank so that that lighting reflections keep changing.

This will stop your Betta fish from focusing on a singular point that may be stressing it out.

Once your Betta fish gets used to the surroundings in the fish tank, it will grow more comfortable with its own reflection in the glass.

This can take up to 3 weeks, depending on the behavior of your Betta fish.

In some cases, you may have to dim the lights above the fish tank to speed up the familiarization process.

If your light is placed at the wrong angle, it can enable your Betta fish to see their own reflection, which can make them uncomfortable for a very long period of time.

Hence, it is best if you take special care of the lighting in and over your Betta fish tank.

Entering the Mating Period

Another known reason for Betta fish to flare their gills is when they are entering their mating period.

When a male and a female Betta fish decide to mate, it is the male’s job to impress the female.

A male Betta fish does this by flaring its gills in order to impress his female companion.

Other than impressing, it is also a power move to express dominance.

A female Betta fish may respond to the male by flaring as well; however, this behavior is not that common.

Before proceeding to the actual mating ritual, you may notice the male Betta fish flaring several times to keep the female Betta fish interested.

Excitement (for Food)

Even though this is a pretty uncommon reason, it is still very much possible.

Some fish owners report they’re Betta fish flaring their gills when it’s time to feed them.

This display of gills is not aggressive compared to the one linked to territorial aggression.

If your Betta fish is playful, it may end up flaring its gills out of happiness or excitement.

Does Gill Flaring have a Bad Impact on Betta Fish?

Based on what we have discussed so far, it is safe to say that gill flaring is something natural in Betta fish.

Regardless of being a natural behavior, there are some problems attached to it.

You should be concerned if your Betta fish constantly flares its gills because it can be bad for its health.

While some may are you that it is a good exercise for their muscles, it is also a display of stressful and aggressive behavior.

If your Betta fish is flaring its gills constantly, it means that it is under a lot of stress.

If you do not put in the effort to reduce these stress factors, it can eventually lead to your Betta fish developing a weak immune system.

As a result, it may become prone to infections and diseases that may or may not be fatal.

Other than this, if your Betta fish stays under constant stress, it may become more susceptible to lack of appetite, loss of color, lethargy, and other stressful symptoms that are common in Betta fish.

These signs usually point towards some form of sickness that is not a good sign of health in your pet fish.

If you feel that your Betta fish is showing any of these symptoms, you should immediately narrow down and eliminate the stress factor or consult a vet for professional advice.

Anything such as glass reflections, lighting, or violent tank mates can be a source of extreme stress for your Betta fish.

On the other hand, if your Betta fish flares its gills occasionally, it is not much of an issue.

It would only help keep your Betta fish physically healthy.

The Bottom Line

In general, the act of flaring is meant to be an intimidating act to fend off any intruders.

It is absolutely okay if your Betta fish flares up occasionally and not all the time because it keeps them in good shape!

Other articles you may also like: