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How to Fix cloudy Water in Your Fish Tank

How to fix foamy and cloudy water in your fish tank? It doesn't look nice at all, and it can be alarming and unsightly!

Many fish aquarists have encountered this particular problem regularly- however, we're going to discuss this issue, why it happens, and what you can do to solve it and prevent it. 

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Top 3 Mistakes Newbies Make Setting Up Their Fish Tank.

A Healthy Goldfish Swimming In Clear WaterA Healthy Goldfish Swimming In Clear Water

Why does cloudy water appear in fish tanks

It's normal for foamy or cloudy water to form several weeks or months after you've set up your tank. Even though having a fish tank with unclear water might look disgusting, it's quite normal if your tank is new. People call this the "New Tank Syndrome."

Bacterial Bloom: New Aquarium

Your tank water may develop this cloudy appearance due to something referred to as "bacterial bloom." In a bacterial bloom, the number of microscopic organisms, begin to multiply. Usually, a microscopic organism is invisible to the naked eye, but when the bacteria grows into multiple colonies, they cause the haziness in your tank water. 

Changes in Nutrients

When you introduce large amounts of new fish into your tank, this can cause your tank's nutrient levels to increase. This can also happen if you overfeed your fish. The high levels of nutrients may make ammonia and nitrite increase, which can be dangerous or even deadly for your fish.  

New cycle of Bacteria

When you introduce medication or anti-biotics into the water, the colony of beneficial bacteria can be wiped out. This can also happen if the water is left completely untreated. Due to this, the good bacteria will try to re-appear, leading to cloudy water. 

Filter Related

Another possible reason as to why your fish tank water may have adopted a milky-like appearance can be due to the filter. If you shut down the filter for a long time and decide to restart it, the water's lack of movement can make the oxygen diminish. The lack of oxygen kills off bacteria.

Replacing the filter will encourage the bacteria to grow again and, once again, will lead to cloudy water.

What causes Foamy Water

Aquarium water can also become foamy, and there are various reasons as to why this happens. The most common sources of foamy water are listed below.

Agitated Water
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Whenever you shake or agitate a liquid, foam or bubbles appear. When you fill your aquarium, it's normal to agitate the water, resulting in bubbles that appear including some foam. One way to avoid this is by pouring the new water slowly, so that the bubbles can dissipate.

Foamy water can also be caused by having an incorrectly set up air pump in your tropical tank. Normally the air pressure within the plastic tubing connected to the air pump can be turned down so that less bubbles appear on the surface of the water.

A Clear Tropical Fish TankA Clear Tropical Fish Tank

Traces of Soap

A common reason for foamy water in your fish tank is that soap gets into the aquarium due to the tools and materials you use to clean it. To prevent this, ensure that the tools you use to clean your tank are only specifically used for your tank and nothing else. Ideally clean and maintain your fish tank yourself - so that you know no-one may have inadvertently used your tools and materials for other cleaning tasks.


Protein-based waste can cause little bubbles to appear as well, and the foam that appears can adopt a foul smell. If the foam is due to an excess amount of protein, then it means it's time to clean out your tank. In other words, clean the filter well and remove any grime and gunk within the fish tank. 

Also, keep an eye on your fish and plants. Sometimes if a fish has died or your aquatic plants are decaying, they become a strong source of protein.

Solutions: Wait It Out

Sometimes, especially if your tank is new - the solution is simple. Do absolutely nothing. Before you decide to add more chemicals or clean it out, be patient and give it at least 2 -3 weeks. It usually clears up on its own. 

Plus, the bacteria that causes the cloudy water is actually good for your tank. By doing things such as changing the filters or adding unnecessary chemicals, you might be harming or killing off the good bacteria.

Add Plants

Plants contain beneficial bacteria and other microorganisms, which help initiate the aquarium's biological balance. They also help to kill off any microbes or bacteria that cause cloudy water. Not to mention, they generate plenty of oxygen, which keeps the water healthy and clear.   

Don't Overfeed

A common fear of rookie aquarists is that they'll starve their fish. Naturally, they develop the poor habit of overfeeding their fish.

By overfeeding your fish, you'll encourage the nitrifying bacteria to break down the waste even more, and they'll do so by multiplying, which will lead to cloudy water. Also, the levels of ammonia and nitrite might increase, and this is often harmful to your fish. 

Add Good Bacteria

By adding more beneficial bacteria, you'll be helping the natural processes of your aquarium. You can buy live nitrifying bacteria at any aquarium shop or online. There are also specific kinds of gravel that contain good bacteria as well.

Air Pump

Your air pump maybe a big reason why your aquarium has cloudy or foamy water, so make sure your air pump is the correct one for your fish tank - (if fitted). Factors such as the type of aquatic plants you have play an essential part in the type of water filter and air pump you should purchase.

Find out the Source

Before putting into practice any of these suggestions, you have to determine the root cause of the cloudy water. Need help? Contact Us, and we'll provide you with the help that you need!

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