10 Reasons Your Betta Fish Died (And How To Prevent It)

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Last Updated on 2023-12-31

When your betta suddenly dies, it can cause heartache, confusion, and worry. Sometimes the answer can be simple, and other times the reason for your Betta’s passing can seem entirely unexplainable. Luckily, there is always an explanation for their death. 

In this article, we’ll find out all the reasons your betta may have died, and more importantly, how to prevent it from happening again in the future!

So, Why Did Your Betta Fish Die? 

The most common cause of death in Betta fish is a poor environment such as unclean water, an ill-kept tank, incompatible fish, too small of a tank, and much more. Betta fish often die from stress which makes it important to manage their exposure to sudden change and monitor the way they react to new things.  

If you start noticing behavior changes in your betta, perform a water test and investigate the results for any chemical imbalances in your water quality. The results of the water test will determine which way you take your investigation. 

What Are the Most Common Reasons Your Betta Fish Might Die?

Even if it does not appear obvious at first, there is always an explanation for your Betta’s. Figuring out why your Betta fish died may take a little investigating, but I urge you to take the time to pry (especially if you take care of other fish) so you can make sure that you do not repeat this with your other fish! 

1. Poor Water Conditions

If there were any recent fluctuations in your Betta’s water, like recent temperature changes or a reduction in their tank’s pH levels, this was probably the reason they died. Betta fish require very clean water conditions, and any sudden changes to their water can cause fatal results.  

Poor water conditions are the leading reason that most Betta fish die, and half the time, you may not realise you were doing anything wrong. A lot of the time, it can be caused due to a fluctuation in pH, ammonia, or even the temperature. So ensuring you’re taking care of all of these is vital so you don’t make the same mistake again!

Maintaining the right temperature (between 76°F to 80°F for a Betta fish) is very important for your Betta fish, and dropping below the required 76°F can be fatal.

It’s also important that your pH level remains constant (pH 7), and any sudden changes in your pH can cause be the reason for sudden death. 

So test the pH, ammonia, nitrite, nitrate and temperature of your tank to ensure that everything in the tank is still stable! (If you don’t already have one, I’d highly recommend purchasing an API Master Test Kit)

Turquoise Betta

2. Stress

Stress can be experienced by any animal, which includes fish! Like many other animals, stress can be life-threatening for bettas which is why you must manage stress carefully. The signs can be difficult to recognize and can be caused by many things like mixing incompatible fish in the same tank together or poor aquarium maintenance.  

Stressful events vary, and although some stress may fade away naturally, it is important that you minimize your betta’s exposure to stress to a minimum. Stress is one of the only ailment that does not kill immediately. Instead, this unique illness can take weeks to kill, which makes pinpointing the exact problem difficult (especially for beginner fish keepers!). 

Stressful events include: 

  • Poor water quality (chemistry or cleanliness) 
  • Poor aquarium maintenance 
  • Aquarium set up incorrectly (ex: size, plants, incompatible number or type of fish) 
  • Malnourishment/overfeeding 
  • Change of environment 
  • Illness/disease 
  • Handling/transport 
  • Rapid water changes 
  • Tapping on glass 
  • No mate or giving up on mating at an old age 

There are many causes of stress, and they all vary in severity. If you recently added something to your tank in the weeks preceding your fish’s death, then this is probably the culprit of your fish’s “sudden”, stress-induced death. It may not have been instant, but the event was a slow buildup of stress. While these deaths may seem inexplainable, they certainly are! 

3. Improper Diet 

Feeding your Betta fish an improper diet is often a frequent reason why your Betta fish died.So make sure you restrict your bettas’sfood intake to roughly 2-4 food pellets per day and ensure that all fish food is approved for your Betta fish. 

Common diet issues: 

  • Overfeeding 
  • Underfeeding 
  • Expired food 
  • Wrong food 

Overfeeding is a major problem for Betta fish mainly because they are the masters of “eyes bigger than their stomach” (only, their stomachs are the size of their eyes!). Given the opportunity, your Betta fish would eat their entire box of food which is why you must be cautious about how much you are feeding them per day. 

An overfed Betta can suffer from constipation, swim bladder disease, weight gain, and even obesity. All of these can impact their quality of life and increase their stress levels. To guarantee you are not overfeeding your Betta, pay attention to the amount of food you are giving them.

In contrast, your Betta can also become malnourished if they are underfed. Bettas become underfed for several reasons, either because of behavioral changes or owner neglect. If your Betta fish has suddenly become standoffish and has stopped eating, this will inevitably lead to malnourishment. 

If your Betta fish was not eating before they died, it is likely they died from some sort of illness or disease which robbed them of their appetite. However, in some cases, they may have starved to death his is especially true if they went longer than ten days without eating,

Feeding your Betta fish expired food can also be deadly. Betta fish are carnivores which means they are eating meat, and it should come as no surprise that expired meat is not good for anybody! 

4. Not Having a Filter in Your Tank

If you saw your Betta gasping at the water’s surface before they died, it is likely that they were not getting the dissolved oxygen they needed to survive. Yep, fish need oxygen in their water to survive (weird statement, I know). Fish get oxygen from surface agitation, which can be created by filters and agitators. 

Creating oxygen for your aquatic pal is very important. So, when there is no surface agitation, this can cause sudden and unexpected death. If you were not using a filter in your aquarium, that is probably the reason that your fish was not getting enough oxygen.  

Not using a filter may also be a contributor to poor water quality, which is one of the top reasons why your Betta fish dies suddenly. Filters are used to help filter debris and chemical waste from your aquarium so your fish can live in clean water. When you do not have a filter, there is nothing to siphon out the waste, and the water eventually becomes toxic! 

5. Improper Cleaning Techniques

If your fish suddenly dies after you clean your tank, you might want to reconsider your cleaning process. From start to finish, you should be considering your Betta’s health every step of the way. When something does not feel right to you, that is probably a sign that you need to reconsider what you are about to do. 

Key things to consider during the cleaning process: 

  • Use a clean bucket 
  • Don’t disturb the gravel too much
  • Let your fish readjust slowly 
  • Pure tap water is poison 

One of the most common mistakes new betta owners make is adding fresh water to the tank that hasn’t been treated with water conditioner, or is at a different temperature or pH level to the water in your tank.

When you do this, it will put your betta into shock which can often cause them to end up dying.

betta care facebook group

6. Disease

There are so many diseases that your betta may end up suffering from and any one of them can become fatal.

Some of the most common diseases you can expect to see in your betta include:

  • Dropsy – Dropsy is one of the main killers of bettas, and if you notice it, the prognosis is never good. In most cases, when you notice your betta has dropsy, it’s time to start considering whether you should euthanise them or not.
  • Fin RotAnother common illness in bettas is fin rot. If you notice your bettas fins are starting to become ragged, then move quickly. Changing the water and adding API Stress Coat can help treat fin rot!
  • Constipation – If you notice that your betta hasn’t been passing stool, or stopped eating, then they may be suffering from constipation. If you notice your betta is suffering from constipation try feeding them daphnia or fasting them for a couple of days.
  • Swim Bladder Disease – And lastly, swim bladder disease is another EXTREMELY common disease that can affect your betta and end up causing them to die. If you notice your betta is suffering from swim bladder disease, then try to give them an Epsom Salt bath or improve the water quality in the tank.

7. Harassment

Another reason that your betta may have died is due to harassment from other tank mates. You may think that bettas would be the bully in your tank, but this isn’t the case. Oftentimes faster fish can nip at your bettas fins wearing them down and stressing them out until they suffer from a disease like fin rot and end up perishing.

8. Old Age 

Old age is the most natural reason for your Betta to die. After reaching around 4 years old, your bright and colorful Betta will start showing you signs of their aging in their appearance in the form of slight fading. 

They may also stop nesting, and it is very common with old age that your Betta will stop interacting as often with you and other fish (if applicable). If your Betta was around four years and you noticed these signs before your Betta passed away, it could have been a sign that your Betta was nearing the end of their life naturally. 

9. Injury

Sometimes it can be injury that killed your betta as well. And when it’s not the injury itself, it may be an infection caused by the injury. So make sure you’re taking anything sharp or damaged out of the tank so your betta can remain injury free!

10. A Poor Start In Life

Unfortunately, sometimes bettas can have a bad start in life which means they’re never going to live a long life. When betta’s are sold in cups and tanks that are too small, it can oftentimes be so stressful that when they’re transported, it’s too stressful and they end up dying.

Blue Betta

How Can You Prevent Your Betta Fish From Dying?

There are plenty of ways to prevent your Betta fish from dying. If you are willing to roll up your sleeves and do a little cleaning, that is.

1. Maintain Good Water Conditions

It is crucial to maintain a clean habitat for your little friend. Take the temperature of your Betta’s aquarium regularly to ensure they are staying between their ideal temperatures of 76°F to 80°F and regular aquarium water readings to gauge their pH level. 

A sudden shift in their pH level or temperature can cause sickness and death, so if you are going to change your pH, you should remove some water or perform a water change to level the water’s pH back out.

And if you have time on your side add things like driftwood and Indian Almond Leaves to lower the pH, and things like crushed coral to increase the pH.

2. Keep The Tank Clean

Even if you have a filter, it is important that you regularly clean your tank. This will guarantee that your fish has clean fresh water. Again, you should always maintain good bacteria, which means you never want to fully dump out 100% of your water.  Instead, change about 15-25% of the water every one or two weeks.

You should also make sure you’re checking the pH, ammonia, nitrites and nitrates once a week to ensure that none of them are rising.

3. Use A Filter And Heater

On the subject of filters, you should always make sure you’re using a filter and heater when you’re looking after your betta fish! Both of which are requires to ensure the water parameters in your tank remain as good as they need to be!

(Check out the best filters and best heaters for betta fish!)

4. Feed Them High Quality Food

To guarantee you are not overfeeding your betta, pay attention to the amount of food you are feeding them and observe their size. Seeing your betta grow at an abnormal rate is a sign that they are being overfed.

To avoid undereating, you should establish a solid routine with your betta. Feed your betta fish 2-4 pellets of food over two separate feedings. When feeding your fish, you should pay attention to the amount they are eating and scoop the remaining food from the top of the water.

Scooping the pellets from the top will help you count the number they have eaten and can be helpful if seeing your fish eat is difficult. Scooping remaining food will also prevent overeating as well! 

5. Minimize Stress 

You will never be able to eliminate stress from your tank, but you can work to meet the requirements of your fish. That means you can take the time to research fish that are compatible with one another and what plants are native to your fish. This helps set up a proper tank and avoid creating a stressful environment. 

If you expose your fish to a stressful situation, try your best to reduce their stress by engaging them in activities they love and situating them in a comfortable and nurturing environment. 

6. Make Sure You’re Acclimating Them

You should also make sure that you’re acclimating your betta as well! There’s no point just adding them to your tank, or dropping new water into the tank without acclimating your betta first. If there not used to the temperature and parameters it may stress them and in some cases kill them!

7. Don’t Overstock Your Tank

When you overstock your tank you’re going to cause all sorts of issues for your betta. Not only will not having enough space stress your betta, but the water quality is also likely to suffer, and you may increase the risk of bullying as well.

(Betta fish care can be a little challenging without the right knowledge. Click here to know everything you need to about Betta fish care!)

What Should You Do When Your Betta Fish Dies?

If your betta fish has died then you still need to act quickly. Especially when you have other fish in the tank as well!

So make sure that you’re removing the body as soon as you see it. Your betta may have died from a disease that could contaminate the water more. Or at the very least it’s going to increase the ammonia in the tank.

Once you’ve removed your betta you should then perform a water change to help keep the other fish in your tank healthy and happy.

Finally, you should then monitor the other fish and the water parameters to ensure there aren’t any more problems in the tank!

Why Did Your Betta Die Suddenly?

Sometimes, it can the case that your betta died so fast, especially if you’re a new keeper. If this sounds like you, then here are the most common reasons that bettas die so fast!

  1. Untreated tap water.
  2. You didn’t acclimatize your betta.
  3. Overfeeding.
  4. No aquarium heater.
  5. No filter.
  6. Changing out too much water.
  7. Aquarium setup doesn’t suit your betta.
  8. Disease or parasites.
  9. Poor water conditions (ammonia poisoning).
  10. Aquarium not cycled.
  11. Overcrowded tank.
  12. The tank isn’t big enough.
  13. Harrassed by other tank mates.
  14. He experienced rough travel.
  15. Jumped out of the water.
  16. Poor decoration choice.
  17. Poor diet.


Do Betta Fish Float or Sink When They Die?

Most Betta fish will sink when they die. It is normal for fish to dig themselves into the sand when they sleep, but it should be a reason for concern when they do this for increased amounts of time.  

Why Did Your Betta Fish Die Young?

There are many reasons that your Betta fish could have died young but the most common reason that your Betta fish died at a young age is improper care or a sudden change of environment. You should pay attention to the things preceding your Betta’s death.  

If you suddenly added something to their tank, this could be an indication of a stress-related death, and if you recently performed a cleaning on their tank, it is likely that the cleaning was performed improperly. 

Will Tap Water Kill Your Betta Fish?

Tap water is dangerous for Betta fish and will slowly kill them. Untreated tap water is full of chlorine and will slowly poison your Betta fish. 

Dechlorinated and conditioned tap water is fine for your Betta fish and is the most used water in home fish tanks! 

Can Betta Fish Die and Come Back to Life?

Unfortunately, no fish can die and come back to life. Therefore, you need to take care of your fish the best you possibly can. 

Is Your Betta Fish Dead Or Sleeping?

Sometimes it can be hard to tell if your betta fish is dead or sleeping, however, one of the easiest ways to tell is by turning the tank light on. If you notice them moving when the light comes on, then you know they’re not dead. But if they’re still not moving, then you may need to swish the water around them to see if they move.


If your fishy family member recently died, the loss can be tragic and concerning. Even though it might be a tough time right now, it is important to take time to understand the reason for your loss. This way, you can change for your future fish care, if needed. 

One of the most common reasons Betta fish die is because of improper tank maintenance and poor water quality, but with the proper routine, you can easily fix this problem in the future. Keep track of your aquarium’s water temperature and take regular water tests to check for quality. It is also important that you make sure your filter is running properly and your fish are receiving proper aeration. 

Before introducing new things to your Betta’s environment, consider whether these things will be compatible with your fish. Betta fishes are highly competitive and are only compatible with select fish. If you put them into tanks with some fish, this can cause high stress and, eventually, death. It helps to do a little research before adopting a Betta. Although these are “beginner’s fish”, they still take a lot of work to care for! 

Ultimate Betta Fish Care Guide
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