How to tell if a Betta fish is stressed?

In this article, we will answer the question “How to tell if a Betta fish is stressed?”. We will also discuss the most common sign of stress in Betta fish and how to calm the Betta fish.

How to tell if a Betta fish is stressed?

The signs of stress in Betta fish are several. However, some of them may look at their usual behaviour. These signs can be from lack of appetite, being off to visual colour alteration and being more vulnerable to diseases. That is why it is recommended to always observe the Betta fish behavioural pattern, then you would be able to tell if the behaviour is natural or altered.

Observations may also help you on detecting stressful conditions and practices. Then, you will be able to reduce or avoid the causes of Betta fish stress.

Signs that a Betta fish is stressed

Spotting ta stressed Betta fish at early stages will allow you to find the best way to remove the cause of stress before your fish develops stress sequels.

There are several signs or symptoms that point to a stressed Betta fish, some of them are:

–       The Betta fish seems to be off most of the time with less swimming activity than previously;

–       The Betta fish can begin to show a lack of appetite: try to detect leftovers around the tank. However, lack of appetite alone may be caused by many issues, not only stress. Thus, it is important to try to detect other signs;

–       The Betta fish will become more prone to diseases: If your Betta fish was healthy and starts showing signs of diseases, it indicates they are vulnerable. This vulnerability can be caused by stressful situations/conditions. Stress makes the immune system weaker, making the Betta fish more prone to infections. In this case, it is important to treat the disease, as well as the stress cause;

–       The Betta fish will start showing abnormal swimming patterns: several conditions may cause swimming abnormalities. Thus, it is crucial to observe and detect the main cause of this. These abnormalities may include rubbing and scratching against the tank structures;

–       The Betta fish will spend more time hiding: if the Betta fish begin to spend more time hiding than usual, it can be an alert of stress. Betta fish can also hide if they are bullied or facing other threats;

–       The Betta fish will begin to have changes in its colours: if the Betta fish begin to lose the vibrant bright colouration, it may be a sign of stress. However, you also need to keep in mind that loss of colour may be involved with depression and even with some diseases. Also, in some cases, it is possible to detect some darker stripes along the Betta fish body, which may indicate they are stressed.

What is stress?

Betta fish stress is very similar to stress in humans, This means the mechanism of stress is practically the same. The stressful condition will stimulate the production of cortisol and adrenaline in the Betta fish body provoking several parallel metabolic disturbances.

There are two different types of stress, long and short term.

Low/long term stress 

The long term stress is the one that is small/weak, however, it happens continuously. In a long term stress atmosphere, a Betta will be continuously working on adapting to the situation. This continuous adaptation will possibly make its immune system weak and make them more vulnerable to health issues, even causing death.

High/short term stress

Another type of stress is short term stress. This type of stress is based on an extremely stressful situation that is not constant. The consequences of high/short term stress only last for a few hours or days. However, the recurring experience of high/short term stress is also very harmful to a Betta fish.

What do stress a Betta fish?

Several factors may provoke a Betta fish to become stressed. Once you can detect the stress causes, you can correct them to avoid further stressful situations for your Betta fish and will be able to keep it happy and healthy.

Common Low/Long term stress causes

Among the several situations that can stress a Betta fish are the ones that are continuous and last longer but are not too strong. The most common lo/long term stress causes are:

–       Small tank: a tank with less than 5 gallons may provoke stress due to limited swimming space. This can result in a bored and even depressed Betta fish too;

–       Overcrowded tank: this cause can also be related to small tanks. This is because if you have lots of fish in a tank that do not have plenty of room, the tank will be small for that community, making it overcrowded;

–       Incorrect or inappropriate water conditions: incorrect water parameters such as temperature and pH can also cause stress in Betta fish. This cause may even provoke the Betta fish death;

–       Lack of hiding spots: hiding spots are very important for a Betta fish. This is because they can use these structures to rest and, in the case of community tanks, they can even hide from any bully.

Common High/Short term stress causes

There are also several reasons for high/short term stress that is harmful to your betta. Below are some of the most common high/short term stress causes:

–       Bullies and aggressive tankmates: Betta fish can be bullied or chased by some other fish species due to their long charming fins and vibrant colours. Thus, it is important to choose your Betta fish tankmates carefully;

–       Sudden fluctuations in water conditions: slowly worsening in water quality will provoke low stress, but if the water changes rapidly it can shock your Betta fish or stress it to death;

–       Diseases: Betta fish illnesses can be parasitical, bacterial, or fungal. This cause can become a long term cause if not treated and can result in the Betta fish death.

How to help a stressed Betta fish

Some actions need to be taken when you detect your Betta fish is stressed. In an attempt of trying to reduce the stress, you can do: 

Frequent water changes

Do not interrupt your water change routine. It is important to keep it running to avoid toxins levels from building up. Evidently, the water changes are going to stress the Betta fish a little. However, stopping changes could stress the fish a lot more. 

Water changes are recommended to be performed once per week or biweekly according to the size of the tank. Water changes are going to reduce the quantity of ammonia and nitrates, making it more friendly for the Betta fish. This will avoid long term stress.

Have a good filtration system

Associated with the water changes is the need for a good filtration system. The cleaner the water, the less stressed the Betta fish. Having a very good filter will allow you to perform water changes biweekly. Thus, the stress caused by water changes would be avoided. 

However, it is crucial to choose a gentle filter. This is because Betta fish prefer slow-moving environments. 

Check the temperature 

Keeping an ideal temperature will reduce the stress on your Betta fish. Thus, having a heater in the tank is recommended to avoid any temperature fluctuations. Sudden temperature changes can even cause fish death.

Avoid/Remove aggressive tankmates

Aggressive tankmates can start bullying and chasing the Betta fish. For this reason, it is fundamental to choose Betta fish tankmates carefully and remove any aggressive fish from the Betta fish tank.

Provide plenty of hiding spots

The best hiding spots you can add to a Betta fish tank are plants. They will help you in mimicking the Betta fish natural environment, will give your tank a very nice look, and will provide plenty of space for your Betta fish to hide and rest. You can also opt for some caves and rocky structures as decorations for your Betta fish tank.

Provide high-quality food items

To strengthen your Betta fish immune system you can reinforce their diet by supplementing it with high-quality Betta fish pellets and live and frozen items.

Provide enough space

Having enough space for your Betta fish to swim around and explore may also help you on guaranteeing your Betta fish happiness and health. Betta fish require a minimum of a 5-gallon tank. Thus, any tank bigger than that could help your Betta fish to feel less stressed.


In this article, we answered the question “How to tell if a Betta fish is stressed?”. We also discussed the most common sign of stress in Betta fish and how to calm the Betta fish.

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

Frequently Asked Questions (FAQs): How to tell if a Betta fish is stressed?

How do you calm a stressed Betta fish?

To calm a stressed Betta fish you will need to determine the stress causes. After detecting the causes, you will have to correct them. However, some actions can be taken to help calm your Betta fish down. Some of them are: run routinely water changes, check water parameters, provide hiding spots; remove aggressive tankmates, and provide high-quality food items.

How do I know if my Betta fish is stressed?

There are several stress signs you can detect on your Betta fish. Among them are colour alterations and stripes, swimming abnormalities, lack of appetite, and too much hiding.

Can a stressed Betta fish fully recover?

Yes, it is possible that your fish will not have sequels of stress. However, it is important to identify the causes of the stress during the early stages. Longer stress periods can even lead to your Betta fish death.

What is the Betta fish normal behaviour?

Betta fish are active, curious fish that enjoy swimming around the tank and exploring. They usually get very excited with stimuli and may reveal this excitement by flaring.

Do Betta fish flare when they are happy?

Not necessarily, Betta fish can get excited by many factors stimuli, such as during feeding time and playtime. However, when a Betta fish is not flaring it does not mean it is unhappy. This will depend on the Betta fish personality.

Do water changes stress Betta fish?

Water changes can be stressful to some Betta fish. This is because they usually do not enjoy strong-moving waters and sometimes the parameters may cause shock and even death if not controlled. 


Stressed Betta Fish Guide (Symptoms, Causes, Treatments).

How To Tell If Your Betta Fish Is Unhappy Or Stressed: 6 Symptoms Of An Stressed Betta. 2020.

Psaradelis, S. 2022. Stressed Betta Fish (causes, Symptoms & Treatments).