Why do betta fish flare?

In this post, we will answer the question “Why do betta fish flare?”. We will also understand some of the situations your betta fish may flare.

Why do betta fish flare?

Betta fish flare in an attempt of looking bigger and more threatening. Betta fish use flaring behaviour to defend their territory from invaders and can also perform this behaviour when they are excited and to stretch.

In nature, animals have different manners of fighting for their lives and protecting themselves from predators. Chameleons, for instance, change colour. Leopard geckos drop their tails. And betta fish flare.

When two male bettas see one another, they flare up. It is a way of making themselves look bigger to defend their territory. One of the evils eventually backs off. If none of the males necks off, they will start a fight. They sometimes fight until one of them ultimately dies.

In the wild, betta fish tend to hide more than stare at each other and flare. Meanwhile, being kept in captivity is different. Due to the limitation of space and hiding spots, betta fish are more prone to flare and fight in tanks.

What does flaring mean?

Flaring behaviour is not always related to aggression and fighting. Betta fish can also flare for other reasons, such as excitement and just for stretching during the day. 

Why is my betta fish flaring after water changes?

Flaring is often a behaviour of fish that have just come into a new home. They are in a defensive mood, if you were in a new place and had no idea what you were in for, you would probably stay defensive too.

Thus, they want to appear intimidating to whatever the threat in the environment is so that it will leave them alone. If the betta fish is flaring at you, it is probably seeing you as a threat at that moment. 

Betta is not capable of seeing us. For starters, humans and bettas’ eyes are set differently-the latter on either side of the body, the former on the front.

They predominantly see colours, movements, and feel vibrations. Thus, going through water changes and tank cleaning may look a bit threatening to them.

Betta fish flaring at the reflection in the tank

Betta fish do not know it is them when they see their reflections in the tank glass or mirror. Therefore, when they see themselves constantly, they continually flare.

Flaring behaviour as a response to threats or invaders should be avoided. A small bit of flaring is good, as it serves to provide exercise for the betta fish, but it should be kept to a minimum.

If you think your betta tank is reflecting your fish, you can try a few changes that might help you on reducing the flaring behaviour. For instance, begin by adjusting the light. You can move the room’s lighting, or if this is not possible, try moving the tank to a new spot. If you cannot move the tank, try adjusting the aquarium light.

If after trying the options above, your fish is still flaring at its reflection, you should try to cover the sides of the tank, leaving only the front open. You can use warm or neutral colours to avoid stressing your betta fish even more with bright or neon colours.

Is Flaring Good for Bettas?

Flaring has some good points. You can encourage your fish to flare. Simply use the small mirror and hold it up to your betta. It might take a few moments before your betta fish sees the reflection. Eventually, you will see all the fins stretched out.

Do not put the mirror into the tank. The mirror should be placed outside the tank just for a short time. Placing the mirror continually would result in stress and exhaustion, and your fish will no doubt end up very sick.

We recommend this stimulus because it is necessary for your fish to stretch and exercise.

Some betta fish may flare due to excitement. Each betta fish has a different personality. Thus, it is possible that a betta flare for excitement and others do not. Also, some of them can associate your figure with the excitement of feeding and playing time.

Betta fish appearance

Fins vary greatly in bettas and can include short tails, veil tails, double tails, delta tails, and a very impressive crown tail, among other types. In terms of colours, this species is found in the most varied shades, that is, bettas exist in a rainbow of beautiful colours.

In the wild, betta fish are usually found in shades of brown or greyish green. However, pet owners can choose their bettas in more vibrant tones, such as red, blue, green, yellow, white, and many others. Some bettas even have a nice metallic sheen to their hues.

How to reduce excessive betta fish flaring?

You should know that betta fish are aggressive and can be very hard to keep with other fish. Even though your betta fish may be a calm individual in comparison to other betta fish, it will sooner or later flare to tank mates. More aggressive betta fish may even nip and bite other individuals.

The other fish will probably not understand the reason for the attack and thus, will not respond aggressively. For this reason, they may end up injured and stressed.

Reflection can be another motive for excessive flaring. If you notice your betta flaring even after you have moved him to his tank, it is likely he will see his reflection of him. Also, try to ensure there is no reflective surface in line with the betta fish tank and check the lighting.

You may have a glare on the outside of your tank due to light coming in. Glares created on the inside of the tank due to light can be enough for your fish to see its reflection and act as though it sees another fish.


In this post, we answered the question “Why do betta fish flare?”. We also understood some of the situations your betta fish may flare.

If you have any thoughts or doubts, feel free to drop us a comment below!

Frequently Asked Questions (FAQs): Why do betta fish flare?

What should I do if my betta fish flares at me?

As the fish becomes used to you and its new home, this behaviour should settle down. Bettas are curious fish, and although it will signal aggression at your presence, your betta will likely stop flaring so much once it becomes used to you. To avoid your betta from flaring at you, you can choose to use softer and smoother movements and a lower voice.

Why is my betta flaring its gills at me?

The most common reason for Betta fish to flare is an intruder into their territory. By widening out their gills, Betta fish appear bigger and this would intimidate the intruder. Flaring may be the result of other aggressive fish in the tank, a human passing by, or a reflection in the glass.

What does a stressed Betta fish look like?

When your betta is facing many stressors, it can start losing its vibrant colours. However, it might develop “stress stripes” on the body. These are horizontal dark- and light-coloured stripes. Additionally, betta fish that are stressed lose their appetite.

Do betta fish flare when they are happy?

Some betta fish flare instinctively when they get agitated by some positive stimuli, such as at feeding and playing times. 

Where does the aggressive flaring behaviour come from?

Betta fish were bred to be aggressive. Thus, the species usually do not consider a non-violent posture toward other fish that seems to invade their territory. In nature, Betta fish usually flare for shorter periods before one of them backs off. However, as captivity limits the Betta fish space and hiding options, the fish end up in fights.

Do Bettas recognize their reflection in a mirror?

No, betta fish are not capable of recognizing themselves in mirrors or other reflective structures. Betta fish treat their reflection as other fish and thus, as a threat and invader.


Why Do Betta Fish Flare Their Gills? https://aquanswers.com/why-do-betta-fish-flare-their-gills/

Betta Fish Flaring – https://www.bettacarefishguide.com/betta-fish-flaring/

Forsatkar, M. N., Nematollahi, M. A., & Brown, C. (2017). Male Siamese fighting fish use gill flaring as the first display towards territorial intruders. Journal of Ethology, 35(1), 51-59.