Betta Fish Dying After Water Change? [5 Possible Reasons]

It is a tragedy when betta fish die after a water change, but it goes to show that betta fish are very sensitive creatures. 

You cannot just do a water change on your betta and then leave the betta out in the open with no cover or protection from their environment. 

The betta needs to be placed back in the tank immediately after changing its water so it can acclimate properly. 

If you have had an unfortunate experience of a betta fish dying after a water change, please read this article for 5 things you should know about how to save your betta’s life!

Betta Fish Dying After Water Change? 

In this article, find 5 reasons why your betta fish die after a water change. Also, find out what to do if this happens to you.

Fish dying in a tank is quite a common thing.  It is often found that when people change the water in their fish tank, they find dead fish floating on top of the water.

Sometimes it appears like the fish are dying after a water change; however, this may not be true always.

The common misconception among aquarium owners is that changing water killed the fish.

So what really happens?

There are many reasons why your betta fish might have died after a water change, but it is definitely not always caused due to the fact that you have changed the water.

5 Reasons Your Betta Fish Dying After Water Change

Betta fish are beautiful, colorful pets that come from the waters of Thailand.

While betta fish can easily adapt to a wide range of different living conditions, betta fish after water change stress is a reaction to something changing in their environment. 

The reason betta fish die after water changing is because there are a number of things that can go wrong during the betta fish breeding process.

5 Reasons Betta Fish Dying After Water Change
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In this section, we will explore some of the most common things betta fish after water change stress and how to avoid them.

Reason 1: The Betta Fish Water Temperature Changed Too Quickly

The first thing pet owners should know is that betta fish do not like changes in their environment.

When the water temperature changes too quickly, or if there is a drop in the level of heat, then this can cause the oxygen levels to decrease inside the betta fish tank.

If there isn’t enough oxygen in the water, then betta fish will drown.

Adding slightly warmer water to slightly colder water can be dangerous for betta fish breeding as the temperature change is too abrupt.

Reason 2: The Betta Fish Water Quality Changed Too Quickly

The second thing to look out for when your betta fish dies after a water change is sudden changes in the water quality.

If chlorine or ammonia levels have increased then betta fish after water change stress can be the result of these sudden changes.

Reason 3: The Betta Fish Were Exposed to Strong Chemicals

The third thing to look out for when your betta fish dies after a water change is an exposure to toxic chemicals.

This can occur if the water spray bottle has previously been used to clean chemicals on the betta fish tank or nearby furniture. 

Bottled water that is safe for human consumption may not be safe for betta fish breeding.

If you are using bottled water, then make sure that it is designed for aquarium use.

Reason 4: The Betta Fish Were Exposed to Toxins

The fourth thing to look out for when your betta fish dies after a water change is an exposure to toxins.

This can occur if the tap water has high levels of chlorine, fluoride, or other chemicals that are not suitable for betta fish breeding.

Before adding any new water into an aquarium, check the water quality using a water testing kit.

Reason 5: The Betta Fish Didn’t Get Enough to Eat

The fifth thing to look out for when your betta fish dies after a water change is the lack of food. If there isn’t enough food available, betta fish can die.

This occurs because betta fish are carnivorous and they need the protein from meat to be able to survive.

If your betta fish is dying after a water change, then this could be because you are not feeding them enough.

How Long Betta Fish Have Been In The Tank/Bag

Another important thing that pet owner should consider if their betta fish dies after a water change is how long the betta fish have been in the tank/bag.

The longer the betta fish are left in the bag, then the means that there is less time for them to adjust to their new surroundings.

How Do You Save a Dying Fish After Water Change?

To save a dying fish after a water change you need to change the water in the tank, but you also need to do something about all that harmful waste.

If siphoning out water does not remove enough of the old water then you should scoop out whatever fish waste remains with a large spoon or cup.

If you are using tap water for your aquarium make sure it is treated with an appropriate dechlorinator and then siphon this into the tank as well.

Now you should refill your tank with dechlorinated water.

If you don’t know how to do this correctly, follow our guide on how to make water safe for fish.

You want to make sure that as little of the old water as possible is mixed with the new water.

This will greatly reduce the amount of ammonia that is introduced into your tank, which will minimize stress to your fish.

This process should be completed within 20 minutes without removing your fish from the water.

If possible, it is advised that you use a gravel siphon to remove as much waste as possible without actually having to scoop it out.

How Do You Save a Betta Fish From Water Shock?

When betta fish get shocked by a water change, they typically develop ich.

Here are some things you can do to get rid of the Ich: 

Use Dechlorinator 

Using a dechlorinator you can remove chlorine and other chemicals present in the water.

Let the dechlorinator sit in the tank for about 30 minutes before you use it to treat your betta fish with ich.

Use API Melafix or Pimafix 

Melafix and Pimafix are natural antibiotics that can be added to the water.

These products should be used according to the instructions on the label.

But try adding a little bit of both together at once to see what works best for your betta fish.  

Increase Heat   

Increase the temperature in your betta fish tank to about 80°F or 27°C.

This will make it harder for ich to live in the water, but make sure you put a thermometer in the tank to keep an eye on things because if it gets too hot your bettas can die.

Limit Light  

Lowering the light in your betta fish tank can also make it harder for ich to live.

Do not turn off the lights completely because you need light for your plants and your betta.

But turn them down as much as possible and use an aquarium timer if necessary.

Increase Oxygenation 

Oxygen is important for betta fish breathing, so increasing the oxygenation in your tank will help your bettas recover.

You can do this by creating air bubbles on the surface of the water with an air stone or you can get a small aerator pump to add more oxygen into the tank.

Also, make sure that there are no water leaks in your betta fish tank.

Prevention is Key 

The best way to stop ich is to never get it in the first place. To do this, make sure that you keep your betta tank clean and always do water changes every week or two weeks.

If you already have ich then act quickly before the betta dies!

If you follow these steps, sometimes your betta will make a quick recovery and come back to life within a few days.

How To Stop Fish From Dying After Water Change? 

Use a Quarantine Tank

This will allow you to observe any new fish for a few days before adding them to the main tank. 

This will allow you to observe and treat (if needed) any sick fish before placing them in your main tank where the rest of your healthy fish reside.

Quarantine tanks are not expensive and can easily be set up with just a small 20 gallon or 10-gallon tank, some gravel or sand (depending on your preference), and some dechlorinated water.

Use Hospital Tanks

You can also use a hospital tank which is usually smaller than the main tank and contains no filter media. 

It will need to be conditioned, but you don’t need to cycle it – just make sure the water is dechlorinated. 

You can use the same gravel or sand that you are using in your main tank.

A hospital tank is great for temporary housing of new fish until they are well enough to be put into the main tank. It can also be used if a fish becomes sick and needs to be treated by a vet.

If you have an emergency, such as the fish seems to be grasping at the surface or is giving birth.

You can move it to a hospital tank until you get time to shop for and set up a quarantine tank.

Use Medications

There are medications available that will treat most common aquarium diseases such as fin rot and ich (Ichthyophthirius multiplies).

These medications are available at most pet stores and over the Internet. 

You can also ask your local fish store for advice on what to use if you have a sick fish that doesn’t seem to be responding to the usual treatment methods.

There are some more resilient fish that do not need special treatment if they become ill, but chances are, if they do get sick and don’t respond to normal treatment like salt or heat, they will need more intensive treatment.

Sometimes medications including antibiotics will be needed and you should ask a vet about this before beginning any medication regimen.

Do Water Changes

You can also do water changes as a form of treatment for sick fish who are already in a hospital tank or quarantine tank. 

This will help lower the amount of ammonia and nitrite in the water which will give your fish a better chance at recovery.

Do not do them if you have other fish in your main aquarium because even though they are usually done with dechlorinated water.

It might be enough to harm some of the other fish, especially if your water is already not very good quality, to begin with.

If you are treating sick fish in a hospital tank or quarantine tank, remember that there are medications that can be used which will often solve the problem without the need for further action on your part. 

Make sure to follow all directions on the label of the medication you are using. 

If your fish doesn’t respond to that particular medication, then you may need to do further investigation into what is wrong with it.

A water change can potentially solve some problems, but it might not be enough in most cases. 

You should still use medications if at all possible or simply isolate the sick fish from the other healthy fish.

These were some of my personal experiences with sick fish.

I have seen fish do well for a while until they are moved to a new tank or treated with medication, then die very soon after the move or treatment.  

Should You Do Water Change When a Fish Dies? 

When a fish dies, you should not do a water change because the amount of ammonia in the water will rise, resulting in a dangerous situation for any other fish still living. 

You can do a partial change instead or wait until the tank is fully cycled again to do a complete replacement of all the water.

Other fish might get sick and die as well if you change the water at the same time as your fish’s death.

So it is best to just wait until all the fish are healthy and doing great before replacing all of the tank water.

What Do You Do After Your Betta Fish Dies?

After a betta fish dies, it is no cause for alarm. Like all living things, this life form will die someday. 

Your betta may have lived to be 5 years old or more, but in the end, it still was just a fish with a predetermined lifespan. 

It is important not to get too emotionally attached to your pet fish. However, after you do lose your betta fish, there are a few things you can do to help cope with the loss.

1. Prevent Future Fish Deaths

After you lose your betta fish, take a moment to reflect on what could have happened. You should try to learn from the mistake that caused its death and prevent it from happening again in the future. 

While hindsight is always 20/20, there are some common mistakes owners make when caring for their pets.

 It is also possible that your betta fish could be sick, and it may simply die without any warning. 

If this happens, read through the rest of the points on this list. While you may not have caused its death, there are other ways you can help yourself feel better about what has happened.

2. Decide How You Are Going to Dispose of the Fish

Even after the fish is gone, its body will remain. 

The first thing to decide is whether or not you want to keep the remains. If you would like to get rid of it right away, there are a few different ways that you can do so.

 The other option is that you do not want to keep the fish right away, but would still like to get rid of it. If this is the case, don’t worry.

3. Mourn Your Fish’s Death

Everyone deals with loss in different ways. There are several ways that you can mourn your fish’s death.

Some people choose to create a funeral ritual that reflects their relationship with the fish.

You can do anything from reading a eulogy or creating a memorial to giving your pet a proper burial.

4. Remember Your Betta Fish for What It Was

Remember to take pride in how long you were able to keep such a beautiful and unique creature alive. 

Bettas are known as Siamese fighting fish for a reason. 

This is the main reason that your betta is such a good choice for people who want pets and do not have much space at home.

Most pet-store bettas only live for two or three years. If you manage to keep yours alive for five years, consider yourself lucky.

5. Take a Deep Breath and Move Forward

In the end, it is just a fish. 

Even if you have a strong emotional connection with your pet, there will come a time when you need to let go.

If you have done everything that you can do to save your fish’s life but it still dies, don’t beat yourself up over it.

In the end, you did your best and there was nothing more that you could have done. All things come to an end, even for ballerinas in fish tanks.

Is It Illegal To Flush a Fish Down The Toilet?

It is not illegal to flush a fish down the toilet. 

Some people think that flushing a live fish down the drain can be hurtful or cruel, but in fact, it’s still better than letting the fish die slowly in its tank. 

A betta fish cannot survive for more than a few hours out of the water unless you take immediate steps at resuscitation, which is not a fun thing to do.

How Do You Know When a Betta Fish Is About To Die? 

There are several ways to tell if your betta fish is dying. The first and easiest way is to watch him on a regular basis. If you pay attention, you will notice subtle changes, such as:

Cloudy Eyes

Betta Fish with cloudy or foggy eyes is a sure sign death is near. Clear eyes are the most effective way to tell whether a betta is healthy or not.

Tattered Fins

Betta fish with torn, raggedy fins are going to die soon. Make sure you have a quarantine tank in case your betta does get sick and needs time to heal before being put back into the main tank.

Not Eating Regularly 

It will be pretty obvious when a betta fish stops eating regularly. If your betta fish has not eaten in days and is also lethargic, he may be dying.


A betta will show his weakness when other signs are present such as cloudy eyes or torn fins.

Weakness is obvious because the fish will stay near the surface of the tank, instead of swimming to the bottom where food is.

Weak betta fish also stay near or float at the top of their tank because they are not strong enough to swim properly.

Fish Laying On The Bottom Of The Tank

A dying betta fish will lay at the bottom of the tank, usually on his side. If your betta fish is taking on the death pose, you should act quickly.

Fish With Labored Breathing

A betta fish with labored breathing will make gurgling noises when he breathes.

If you are not familiar with this type of noise, it is definitely time to check up on your fish.

Betta fish usually have an upright tail, but one that is drooping or not upright can be a sign of distress.

There are even more signs you can find that will help you determine how your betta fish is doing. Below we mentioned an article that focuses on betta fish behaviors before death.

If you notice any of these signs, it may be time to call your doctor (veterinarian) for an appointment.

Read this article next: Betta fish behavior before death! 7 Signs you must know.

How Long Does It Take Betta Fish To Adjust To a New Tank? 

Betta fish do not adjust well to a new environment. 

A betta fish becomes stressed when another fish is introduced into its territory, or when it has been moved to a new tank because of water parameters, overcrowding, bullying, or deteriorating water conditions in the old tank.

To avoid shocking your betta fish and make it feel more at home in its new environment, do not add it to the tank immediately after you get it home from the pet store.

Let your betta fish rest in the plastic bag for about an hour or so before releasing it into its new tank.

This will give him/her time to adjust to the temperature difference between the water in the plastic bag and the water in the tank.

Once your betta fish has been released into its new environment, it will take days before it starts to become active and show off its beauty.

It will take weeks before he/she starts eating regularly.

It takes several months for a betta fish to adjust fully to its new environment and start behaving normally.


In conclusion, betta fish should be isolated in a hospital tank or a quarantine tank while you change the water.

Also, put a water conditioner into the new water to detoxify it from chlorine and chloramines.

This will make sure your betta fish does not get sick from the water change.

You need to do a 50% water change every 2 or 3 days with conditioned water.

You also need to feed your betta fish only half the amount of food daily to keep their digestive system healthy.

Finally, you can’t keep a sick betta fish in a small container and expect him to get better.

This is why he gets sick and dies after a water change even though you did everything right.

Have you ever experienced your betta fish dying after a water change? Let me know in the comments below.

Thank you for reading this article. If you liked this article, please share it with others so they don’t make the same mistake.

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