Skip to Content

12 Tips To Save Dying Fish After A Water Change

12 Tips To Save Dying Fish After A Water Change

How To Save Dying Fish After A Water Change: Fish Care 101 

Today we are going to talk about one of the most tragic incidents that mostly happens when we change the aquarium water. If you have been keeping an aquarium for an extended period, then you have probably noticed it happening.

One or two of our fishes die after a water change routine without any reason. Now the most certain question rise in our mind is – How to save dying fish after a water change

So, that’s why we need to know what’s are the possible reasons that encourage this kind of incident and how to stop or save our fish from dying. We can’t avoid water change routines as it is one of the crucial factors that decide the longevity of the fish life. So, what to do then?

I have shared a detailed article with you on how to save dying fish after a water change. Note: If you want to save the aquarium inhabitants’ life or you want to avoid happening such a thing, then you must go through the complete article.

So, before we learn how to save aquatic inhabitants from dying, we must know why water changes are important? 

Do you know How to save dying fish after a water change?

Short Video on How to Save Dying Fish after a water change

You must learn why aquarium changes are important and what are some underlying problems that could end up your fish life.

Read Also  

How Long Can A Betta Fish Go Without Food – Explained

Assessing the Problem

First of all, you need to assess the problem that is causing death. There can be many potential reasons that lead your inhabitant to death. If your fish died quickly, it was most likely caused by one of these problems or issues:

You ignore or forgot to De-Chlorinate the Water

Some peoples think that setting up an aquarium is a piece of cake – they just need to buy an aquarium, pour some water in it or just directly throw the fish inside that tank. But this is wrong!

The case is not the same as humans, they can’t live or survive on tap water as it contains chlorine. You need to treat the water before you use it.

You should de-chlorinate the aquarium water thoroughly to make sure it’s suitable for fishes, they will just die in a few hours. 🙁

Possibly due to New Tank Syndrome

Well, it’s the most probable common mistake that beginners make when they buy an aquarium. You must cycle the tank. Waste produced by fishes breaks down into ammonia which is toxic for fishes.

Sudden Changes in Ph level of water

Sometimes, we in our busy daily schedule forget to check the temperate or ph level of our aquarium water. Just dumping your fish straight into the tank is a big, big mistake that we do. Dumping a new fish straight into the tank is a kind of shock for them.

You should acclimate the fish tank and your new fish to reduce the risk of shock.

Your fish was sick

Maybe, your fish was already sick when you bought it from the store. Many folks think they did something wrong that ended their new fish life but that’s not the only case. There is almost at least 13% of fish being sold that are already sick.

You are changing aquarium water in the wrong way

Yes, changing the water of your aquarium can lead them to death too. Changing the water of an aquarium is a drastic shift for aquarium inhabitants.

Not all the fish can tolerate this, that is why you may have noticed one or two fish getting sick or worse like death.

Water changing routine occurs a sudden change in water chemistry and tank temperature. The most common problem of the water changing routine is water hardness.

You need to soften the water before you replace it with the tank water because fishes can’t tolerate the water’s hardness.

Another problem with the routine is they can kill off the bacteria that is beneficial for your fish. Not all bacterias are harmful, some of them are beneficial too like they regulate and maintain the nitrogen cycle of the water.

Separate your sick fish as soon as possible from the healthy ones.

12 Tips To Save Dying Fish After A Water Change
Separate your sick fish as soon as possible from the healthy ones.

Yes, you need to separate your sich fish if you have one, from the healthy inhabitants. It will reduce the chances of other fishes or inhabitants getting affected by your sick fish.

You may have noticed that in the first hour, one of our fish starts tp act lazy or sick then just after a couple of hours, you fund that more than one is struggling to survive or die.

Check the water quality

After replacing the healthy fishes and separating the sick ones, you should check the water quality – check the temperature of the water before you add it to the aquarium. Now, check the hardness of the water, if it is hard then consider softening it.

You can check and follow this article “how to soften hard water for your aquarium“, I have shared some easy and effective ways to reduce the hardness of the water, step-by-step.

Lean the tank and change the water

As soon as you are done with the water hardness, you can just lean the tank and change or replace the water in your tank. Just make sure not to change the whole water, just replace 70% of an aquarium existing water.

Check your fish

After, replacing the water, check your fish every 10 to 15 minutes for a few hours. If you find them getting less active then you did something wrong, maybe you skipped a step. If you follow the steps closely, I am 101% sure that they will be alright.

Reviving or Saving Your Aquarium

Now, If you have any sick fish then there is something that you can do to save them or help them. Of course, you can’t revive your fish from dead but you can save your fish at least from death.

So, how to save dying fish after a water change? The answer is – By following these steps 🙂

Identify symptoms of a dying fish.

First of all, identify what is wrong that causes them to behave lazily. Look for the signs or symptoms of a dying fish.

The most common signs of dying fish after water change are:

  • They are swimming upside down, behaving or appearing disoriented
  • Sick or Unhealthy fishes leave food uneaten
  • White spots on fins or body of your fish or Discolored gills in your fish
  • They may struggle in breathing like gasping at the surface of the water.
  • They may have bulging eyes
  • They may rub themselves on hard surfaces.
  • They may start bloating
  • They may have skin sores on their body
  • Change in their shape or size

How to save dying fish after the water change

12 Tips To Save Dying Fish After A Water Change
  • Remove the filter and treat the water.

If you see any of then signs, then, first of all, you need to remove the filter from the aquarium and treat the water effectively as soon as possible. Just as I told you, work on the ph or temperate level of the water.

  • Look for symptoms in other fish.

As soon as you are done with treating the aquarium water, you need to perform a quick check on your other aquarium inhabitants. You must look for symptoms in other fishes as well as they might also feel sick.

  • Treat the water with a heat and salt method

Apart from softening your aquarium water, you should also treat the water with a salt and heat method. Don’t underestimate this method, even the method is old, the heat & salt method still works

  • Feed your fish veggies and low protein foods.

Now, try to feed your dying fish with low protein foods and excise parasites with tweezers. Wait for a few minutes, if you notice no improvement then it is time for a commercial fish medication but if your fish is struggling more than a few minutes ago.

Then I am sorry, but I think that you are late to save him but you can comfort a dying fish at least. Sadly, he is dying but you can make them feel comfortable at least and say goodbye.

I will be honest, in my 3 years of experience, I have seen most instances of fish dying can be put down mistakes made by the owner. But it’ okay, incidents happen and you shouldn’t be ashamed or beat yourself over it. It’s Life and we all are to learn from experiences.

You can, at last, prevent this from happening. The best way to save a fish from dying water is by preventing it from happening. So, nothing can be better rather than preventing such circumstances from happening during the water change.

Everybody should know that prevention is better than cure and is the best medicine.

How to prevent fish from dying from water change?

Check the quality of the tap water.

Before you replace water, you should check the tap water ph or temperate level and decide whether it is ideal for your fish or not. If not, treat it well and make it ideal. Also, check the temperature of the water, an ideal temperature is 25-degree Celcius to 27-degree Celcius for most of the fish breeds.

Maintain water quality

After replacing the aquarium water, you should monitor the quality of the water. Setting up an aquarium or replacing its water is an easy task than maintaining it. Maintaining the water quality in an ideal manner is a big job.

Clean the tank regularly.

The most important thing that you should be doing is the regular cleaning of your tank. Look, most people don’t realize that the waste released by the fish in the tanks breaks down into ammonia which is toxic for fish.

Regular cleaning will help in removing the waste as well as uneaten food that might lead your fish to sick or even worse like death.

Feed fish a varied diet.

If you have more than one type of fish breed in your tank then it is a must to feed your fishes with a varied diet. Not all breeds can get their proteins and other essentials from the same diet.

Separate infected fish from healthy ones.

If you notice a fish getting sick, the first thing you should consider doing is separating it from the healthy ones to keep them from getting affected. An infected fish can infect other fishes too, so it is must separate them first.

The Dos and Don’ts of Aquarium Water Changes

12 Tips To Save Dying Fish After A Water Change

What not to do?

  • Throwing untreated water into the tank.
  • Keeping your fish in poor water quality.
  • Avoiding quality gravel vacuum.
  • Changing 100% of aquarium water.
  • Ignoring De-chlorinating Water.

What to do?

  • Treat the water effectively before pouring it into the tank.
  • Maintain water Ph level.
  • Invest in Quality Gravel.
  • Change only 40% to 60% of aquarium water.
  • Remove chlorine from the water with a water conditioner.

Some Common Mistakes That People Makes With Their Aquarium

12 Tips To Save Dying Fish After A Water Change
Some Common Mistakes That People Makes With Their Aquarium

Starting Too Small

Many beginners prefer to start with mini-aquarium packages but mostly this kind of choice ends up with courting failure. Putting numbers of fish in a small tank having small water volume, make them feel stressed and leaves no room for error.

It doesn’t mean that you have to go for a 20-gallon tank, you can start with at least a 5-gallon tank. Less than 5 gallons is not preferable.

Adding Fish quickly

Everyone enjoys adding new and colorful fish in their aquarium as it enhances the beauty but most of the new aquarium owner tends to add fish on the same day in their aquarium. But this is completely wrong, you need to wait at least 24 hours before you put them in your fish.

You may ask- why should wait, well for the answer – you have to check this article – why should I wait for 24 hours before adding fish in an aquarium?

Adding Too Many Fish at once

Everyones want to fill their tank with a variety f inhabitant but adding too many fish in an aquarium and plus all at once is the biggest mistake you can make.

You should start and go slow. You need to give you take some time so that it can develop established beneficial bacteria colonies.


No doubt that it’s the most common mistake that many folks make once in their lifetime. Overstocking your aquarium is disastrous. Even you have seen some people keeping 20 fish in 10-gallon tanks, you can’t do that as they are experienced ones, for the beginners, it would be disastrous


The number mistake that you & most peoples make is overfeeding their fish you can just feed them all the time. Even fish tend to seek food all the time, you don’t need to feed them all the time. You should not feed them more than once a day or even twice if needed. But twice is enough.

Not changing the aquarium water

You should at least change your 40 percent aquarium water once a week. But use only treated water. Make sure to use a water conditioner and de-chlorinator in your aquarium water.

Read Also

5 Effective & Easy Steps to Clean Aquarium Sand


A complete water change can make your fishes horribly sick and not treating the water before replacing it with the aquarium water can also lead them to death.

Therefore, it is essential to treat the water effectively and then replace only 40 percent of the aquarium water.

Plus, you also need to separate sick ones from the healthy ones if there are sick ones present in the aquarium. Otherwise, you don’t need to do so but you do need to clean the tank regularly to avoid any fish getting infected from toxic ammonia.

I hope, you find this article ” How to save dying fish after a water change ” helpful, I am just curious about what type of fish breed do people love for a pet? Leave a comment if you pet goldfish in your aquarium and if you don’t, then tell me your favorite fish breed! 🙂

Do you have any stories related to this post – how to save dying fish after a water change? Is there any fish that died recently? What was the reason behind this? Do let me know down in the comment section. Do you know how to save dying fish after a water change?