Why Did Your Betta Fish Die? (And How To Prevent It)

When your Betta bestie 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 your fishy friend’s death. 

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 take, 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 an aquarium 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 bestie passing away. 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 fishy family members! 

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, but any changes to their water can cause fatal results.  

Poor water conditions are the leading reason that most Betta fish die, and half the time, their human companions had no idea they were doing anything wrong. This is because of wrong water being used, putting your fish in your water too early, and having the wrong temperature water. 

Maintaining the right temperature (between 76°F to 85°F for a Betta fish) is very important for your Betta fish, and dropping below the required 76°F can be fatal. It is also important that your pH level remains constant (pH 7), given any changes in your pH can cause be the reason for sudden death. 

To understand whether it was poor water conditions that caused your Betta fish’s sudden death, start with an aquarium water test. This will tell you the pH levels of your aquarium as well as any other chemicals that you add to your tank. You should also take a reading of the temperature of your tank. The results of these will help you determine whether the conditions of your water were sustainable for your fish. If they were not, you know any future tanks will need to be adjusted accordingly.  

Turquoise Betta


Stress can be experienced by any animal, which includes fish! Like many other animals, stress can be life-threatening for fish 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 fishy friend’s exposure to stress to a minimum. Stress is one of the only fish illnesses 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! 

Improper Diet 

Feeding your Betta fish an improper diet is often a frequent reason why your Betta fish died. You should restrict your colorful companion’s food intake to roughly 4-6 food pellets per day and ensure that all fish food is in date and 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 fatal digestive obstructions, 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 and carefully observe their size. 

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 starvation. This is especially true if they went longer than five days without eating, which is the longest possible duration you should go without feeding a Betta in captivity. If your Betta is not eating, you should be exploring every way you can to get them fed. 

Feeding your Betta fish expired food can 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! 

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 surface agitation.  

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. Water filters are used to help filter biological 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! 

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 
  • Keep the good bacteria 
  • Let your fish readjust slowly 
  • Pure tap water is poison 
  • Let chemicals evaporate first! 

One of the most common mistakes people tend to make when they are cleaning their aquariums is during the transportation process when moving their Betta from their aquarium to their temporary bowl. While in their temporary bowl or bucket, many beginner fish owners will fill up a random bucket with tap water and plop their fish right in, but the lack of consideration for their fish’s well-being is dangerous and can lead to death. 

Another common mistake many people make is by adding their fish into the water too soon before chemicals have evaporated. Be prepared to let the chemicals and air bubbles settle before you put your Betta back in their aquarium. 

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 their human companions 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. 

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.

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

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 85°F and regular aquarium water readings to gauge their pH level. 

Even the slightest shift in their pH level can cause instant death, so if you are going to change your pH, you should remove your Betta from your aquarium and put them into a Betta-safe tank where they can remain until the water conditions are at levels that allow your Betta fish to thrive. 

Keep a Clean Tank

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. 

Feed Proper Food

Overeating 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. // scoop the surface of the water for food// 

To avoid undereating, you should establish a solid routine with your Betta. Feed your Betta fish 4-6 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! 

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. 

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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. 


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! 

If you liked this article, make sure you check out the rest of the website! And if you have any more questions, you can ask them in the Q&A Section!