Can Goldfish Live In Dirty Water? (How To Change Dirty Water?)

As a fish keeper, you must want to know about the water requirements of your fish before adding them to your tank. Is it okay to keep your goldfish in dirty water? Can your goldfish survive in dirty water? Let us discuss this below:

Goldfish cannot live for long in dirty water as it can lead to significant health issues like swim bladder disorder in goldfish. Excessive feeding and no regular water change are the common reasons for contaminated water. We advise maintaining good quality water to avoid any harm to your fish.

Let us dive into the article to know more about how contaminated water affects your goldfish. In addition to this, we will also discuss how to change the dirty water from the tank. 

Water requirements of goldfish?

Water Temperature68-74° F
Ph level 7.5
The above table shows the ideal water parameters for goldfish.

Water Temperature 

Goldfish can thrive up to a temperature between 68-74° F. It will always be advisable to maintain adequate water temperature in your goldfish tank. Inadequate water temperature can lead to significant health issues for your goldfish. 

Also read: What Is The Ideal Water Temperature For Goldfish?

Water Ph level 

The ideal water Ph level of your goldfish tank is 7.5. We want you to know that there is a connection between water Ph level and water hardness.

If the water Ph level of your goldfish tank is higher, then you must maintain a high water hardness level. 

Therefore, it will always be advisable to maintain the adequate water Ph level and temperature in your goldish tank so that your fish can live a healthy life. 

Also read: Best PH Level For Goldfish?

How to determine if your goldfish tank is contaminated?

Here are the ways to determine whether your goldfish tank is dirty or not :

  1. If you discover leftover food particles or waste in the tank, it indicates that the water in your goldfish tank is dirty.
  2. If you find debris appearing when you stir up the gravel, it shows contaminated water in the tank.
  3. Overcrowding the tank can also make the tank water contaminated. 

Reasons for a contaminated tank?

Here are the reasons for a contaminated tank: 

No regular water change

One of the most common reasons for dirty tanks is no water change. You should always ensure regular water to keep your goldfish tank clean. Contaminated water can cause significant health issues to your goldfish.

Excessive Feeding

Goldfish are messy fish that produces a lot of waste in the tank. Excessive feeding to your goldfish will make them produce more waste, leading the tank water to get contaminated in no time.

Also read: What Happens When You Overfeed Goldfish?

Small size tank

Adding too many goldfish to a small tank can contaminate the tank’s water as goldfish are messy fish that produce a lot of waste.

Plants in the tank

Plants in the tank, once decayed, can make the water dirty.

Also read: Do Goldfish Eat Plants? 

Passed away goldfish

If your goldfish has passed away in the tank and you failed to remove it from the tank, then it will rot and contaminate the tank’s water.

These were some of the reasons behind the contaminated tank.

Also read: How To Humanely Euthanize Goldfish?

How does dirty water affect your goldfish?

Dirty water affects your goldfish in the following ways:

Swim bladder disorder

Contaminated water can lead to swim bladder disorder in your goldfish. Swim bladder disorder can make your goldfish fall ill.

So, it will always be advisable to keep the tank’s water clean to avoid swim bladder disorder in your goldfish. To know more about swim bladder disease in your goldfish, you can read my article Why can’t my goldfish swim


Contaminated water can also lead to various diseases in your goldfish, leading to the passing away of your fish.

Avoid food

You goldfish can lose its appetite due to the dirty water in the tank. Once your goldfish loses its appetite, it will not be able to eat its food. So in such a case, your goldfish will prefer to avoid food.

Lack of oxygen

Contaminated water can also lead to a drop in oxygen, making your goldfish gulp air at the water surface. Lack of oxygen can lead to various health issues in your goldfish.

Also read: Can Goldfish Live Without Oxygen? 

Harmful bacteria

The leftovers in the tank can also lead to the spike in the tank’s ammonia level leading to ammonia poisoning in your fish.

Therefore, it will always be advisable to clean your goldfish tank regularly to avoid any harm to your goldfish.

Also read: Ammonia Poisoning In Goldfish

Can goldfish pass away in dirty water?

Your goldfish will not survive for a long time in contaminated water and eventually will pass away in some time. However, dirty water can lead to serious health issues in your goldfish.

Although goldfish are robust species, they will not handle contaminated water long and will pass away.

We want you to know that goldfish can also jump out of the tank if the water is dirty. Therefore, it will always be advisable to provide good quality water to your goldfish for proper growth and development.

How to change the dirty water?

Changing dirty water is very important to avoid harming your goldfish as dirty water produces harmful toxins in the water that can cause significant health issues to your goldfish.

We want you to know that smaller tanks require more frequent changes than a big size tanks. So, you can change your goldfish tank’s water by following the below instruction.

You should always start the water change by replacing only 5 percent of the water and then changing the water in small volumes every week.

After that, it would be advisable to increase the percentage of change every week. This process will help your goldfish adapt to the water change and not get stressed due to the slow water chemistry change.

With time, start changing 30% water weekly to maintain the tank’s water quality.

It would not be advisable to replace the total water from the tank as it will make it difficult for your goldfish to adapt to the water change, leading to stress in your goldfish.

In addition, you must ensure to keep your hands clean while changing the tank’s water. Make sure that there is no soap in your hand, as soap can cause harm to your goldfish.


  1. The ideal water temperature of your goldfish tank is between 68-74° F, and the water ph level is 7.5
  2.  Any leftover particles or debris indicate the contaminated water in the tank. 
  3. There are many reasons behind the dirty water, like no regular water change, decayed plants, or a small tank.
  4. Dirty water can lead to significant health issues in your goldfish, like swim bladder disorder.
  5. Your goldfish will not be able to survive in polluted water for long and will eventually pass away.
  6. Therefore you should always provide clean water to your goldfish to avoid any harm to your fish. 

Reference: ResearchGate

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