EVERY Cause Of Cloudy Aquarium Water (& What To Do)

Many aquarium keepers have experienced the frustration of cloudy water. Not only does it decrease the aesthetic value of your aquarium, but in some cases, it can even prove fatal to the fish living there. This is something that many aquarists may have gone through at some point. Cloudy aquarium water can have a variety of causes, including bacterial bloom or an excess of nutrients. Cloudy water can typically be traced back to one of two primary factors based on its color and the surrounding conditions. To help you figure out what’s making your aquarium cloudy, we’ve listed a few potential reasons down below.

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Why Is Your Aquarium Water Cloudy?

Having cloudy water in your aquarium can be a bit disheartening, but the good news is that it’s usually a sign of an easy fix. Here are seven common reasons why your aquarium water might be cloudy: 

1. New Tank Syndrome

When you first set up a new tank, the water may appear cloudy due to a variety of factors. That includes the amount of oxygen in the water, how quickly you added fish to the tank, the water quality, and if the new substrate is thoroughly washed.

2. Overfeeding

If you’re overfeeding your fish, their leftover food can cause cloudy water due to a bacterial bloom. This can also occur if you are adding too much flake or pellet food to the water.

3. Bacterial Bloom

This occurs due to a sudden spike in bacteria levels in the aquarium making it cloudy, often caused by new fish being added or an increase in the amount of organic matter. It could be caused by too much light in the aquarium.

4. Nitrate Build-Up 

When there is an excess of nitrate in your tank, it can cause cloudy water. This is usually a result of an overload of fish waste or uneaten food.

5. Algae Bloom

If you have high levels of light and nutrients present in the aquarium. This can sometimes create an algae bloom which will make the water appear cloudy.

6. Aquarium Decorations

If you have decorations in the aquarium, they can sometimes make your aquarium cloudy due to a buildup of algae or bacteria on them. You can avoid this by regularly cleaning your decorations.

7. Phosphates

If the phosphate levels in your tank are too high, it can cause the water to become cloudy due to an algae bloom. You can test the phosphate levels in your tank and adjust them if necessary. 

Cloudy water in aquarium. Bacterial bloom. Beautiful freshwater aquascape with live plants, Frodo stones, redmoor roots covered by java moss and a school of blue neon tetra fish.

How Do You Fix Cloudy Aquarium Water

 Are you experiencing cloudy water in your aquarium? Cloudy aquatic conditions can be caused by a variety of issues, but luckily there are some straightforward steps that you can take to improve the clarity of your tank.

1. Regular Water Changes

A key factor in ensuring clear and healthy aquarium water is doing regular water changes. This will help remove excess nutrients and organic compounds that can cause cloudy water.

2. Check Filter 

Make sure your filter is working properly and is not clogged with debris or other materials that could be causing the water to become cloudy. Clean or replace the filter if necessary to ensure it’s running optimally.

3. Utilize Carbon 

Activated carbon is a great way to help remove organic compounds and other materials that can cause cloudy water. Add some carbon to the filter or directly into the tank itself; just make sure not to overdo it, as this could lead to additional problems.

4. Increase Filtration 

If your filtration system isn’t powerful enough for the size of your tank, this could be causing cloudy water. Consider upgrading your filter to a better model if necessary.

5. Check Algae

If you have an algae issue in your aquarium, this could also be the reason why your aquarium water is cloudy. Use an algaecide to treat the problem, and then vacuum out any dead algae from the bottom of your tank.

6. Regular Maintenance

Keep up on regular maintenance of your aquarium, such as cleaning the glass and any decorations, testing the water parameters, and removing excess food particles or other debris that can make your water cloudy. Your fish will thank you for it!

7. Clarifying Agents

If all else fails, there are products available that can reduce cloudy water and help clarify the water in your tank. Be sure to read the instructions carefully before using them, and make sure they are compatible with your aquarium setup. 

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Why Is Aquarium Water Cloudy After Water Change

Aquarium water can quickly become cloudy after a water change, leaving you wondering what could be causing the problem. While some problems may require professional help, there are several common causes that may be to blame for cloudy aquarium water after a water change.

1. Bacterial Bloom 

A sudden increase in beneficial bacteria in your aquarium after a water change can cause it to look like the water is cloudy. This usually occurs when new substrates, plants, or décor are added to the tank that contains bacteria spores. The bacteria consume organic matter and will eventually die off, returning your aquarium to crystal clear.

2. Overfeeding

It’s important not to overfeed your fish after a water change, as this can cause excess waste in your aquarium. Uneaten food and fish waste can rot, leading to cloudy water.

3. Old Filter

When the filter isn’t working properly, it won’t be able to remove the particles that cause your aquarium to become cloudy, even after a water change. Make sure you follow the manufacturer’s instructions for filter maintenance and replace it if necessary.

4. Algae Bloom

Algae blooms can be caused by too much light, unbalanced nutrient levels, or an overabundance of food. If left unchecked, algae will quickly take over your tank and cause the water to become cloudy even after a water change.

5. Sand Storms

Sand storms occur when the sand particles in your aquarium are disturbed, usually due to strong water currents or air bubbles. This can create a cloudy haze in the tank and should be avoided as much as possible.

6. High Ammonia Levels 

High ammonia levels are toxic to fish and can cause cloudy water, along with other problems such as disease and death. Test your aquarium’s ammonia levels regularly to ensure they remain at the proper levels.

7. Unbalanced pH Levels 

When there is an imbalance in your aquarium’s pH levels, it can cause cloudy water as well as other problems such as fish stress and disease. Test your aquarium’s pH regularly to ensure that it remains within the optimal range for your fish. 

Why Is Your Aquarium Water Green and Cloudy

Don’t feel bad if the water in your fish tank turns green. Green water in aquariums is a common problem for pet owners. There are a number of potential causes of green water, all of which involve an algae bloom.

1. Algal Bloom

An excessive concentration of organic nutrients like phosphorus and nitrate in the water is the usual culprit in algal blooms, which results in cloudy water. The spores feed on these substances, which can be prevented by lowering the phosphorus and nitrate to normal levels.

2. Direct Sunlight

Algae rely heavily on light for photosynthesis. Algae in an aquarium can grow rapidly if your aquarium is exposed to direct sunlight because photosynthesis is stimulated by light. Your tank may be overexposed to light from a window even when the tank light is turned off.

3. Overpopulated Tank

Algae blooms are caused by an overpopulation of fish, whose waste products enrich the water. Water plants and algae benefit from the nitrogen in fish waste.

4. Overfeeding

We sometimes feed our fish too much, which leaves a lot of food floating around in the aquarium. When there is too much food left, it turns into nutrients that algae use to grow.

5. Lack of Tank Maintenance

Your aquarium needs to be taken care of on a regular basis to keep the water from turning cloudy and green. Simple things like changing the water, cleaning the filter, and testing the water quality are important for the tank’s environment. If you don’t do these tasks frequently enough as you should, you could be making algae grow faster than it should.

6. Nutrient Imbalance

To grow, the plants in your aquarium need the right mix of nutrients, but algae also eat those nutrients. Having too many nutrients or too few of it could throw off the balance and make it possible for algae to grow.

7. Green Dust Algae

If the water in your aquarium is green, it might not be the water. Instead, it could be green dust algae. A green film of green dust algae grows on rocks and, most noticeably, on the walls of planted tanks. 

Why Is Water Cloudy In New aquarium

It’s annoying to put in all that effort to set up a brand-new aquarium only to have the water cloud up on you. This is perfectly normal, and there are several explanations for it. Here are some reasons why your water is cloudy in the new aquarium.

1. Bacterial Bloom

Bacterial bloom is a sudden rise in the number of bacterial colonies, usually in the water column. The bacteria grow so rapidly that they can be seen with the naked eye, making the water look cloudy.

2. Residue From the Gravel

The gravel or substrate which is used in aquariums can make the water look cloudy. If it isn’t washed well before going into the tank, it can make the water cloudy in just a few minutes. 

3. Wrong pH Levels

The water in your fish tank could also be cloudy if the conditions are not right. This generally indicates that the water has a high pH and a bunch of dissolved metals.   Get a water testing kit and test the water in your aquarium to see if the conditions of the water are making it cloudy.

4. Bacteria From Filter

Cloudy water in your aquarium could be caused by a bacterial bloom if you just put in a new filter or turned on the one you already had after a long time. This tends to happen because the good old bacteria die and are replaced by new ones. Most of the time, this makes the water in the tank cloudy or milky.

5. Bacterial Bloom Due to New Bacteria Growth

There are many things that can kill the good bacteria in your tank, including changes in the water conditions. When these bacteria start to grow back again, they can make your aquarium water cloudy. Most of the time, this tends to happen when the water is back to normal. 

6. Algae Growth

The growth of algae can also make the water in your tank look cloudy. In this particular instance, the water in the tank turns green and cloudy. Most algae grow when they are exposed directly to sunlight or some other type of light source. In some situations, algae can grow quickly and make the water in your tank cloudy, even if you don’t have any fish in it.

7. The Water Is Not Clean

Your brand-new tank might also be cloudy because it is not full of clean water. If the water is dirty, it can make your tank look cloudy once you fill it up. To avoid making this mistake, have your water source checked to see if it’s clean enough to use as aquarium water.

Causes of Cloudy Water in Established Aquarium

It’s a huge deal and a huge accomplishment to get a fish tank and get it set up. This is why it bothers us when our aquarium water becomes cloudy. Learn the causes of cloudy aquarium water by reading on.

1. Gravel Residue

It’s likely that the gravel wasn’t washed well enough, which would make the water in the tank cloudy an hour or two after it was filled. Empty the tank and run clean water through the gravel until the water comes out clean. If you do that, the problem should go away.

2. Dissolved Constituents

A high concentration of dissolved substances such as phosphates, silicates, or heavy metals is likely to blame for cloudy aquarium water if washing the gravel doesn’t solve the problem. The water is likely alkaline if tested for pH. A simple adding of water conditioners typically solves the issue.

3. Excess Nutrients

Phosphates and nitrates, for example, both promote algae growth which causes cloudy water. If you don’t overfeed your fish, phosphates and nitrates won’t build up as quickly. Even though changing the water will help right away, it probably won’t be the final solution.

4. Excess Fish Waste

Over time, the aquarium’s nitrate levels will rise naturally due to the accumulation of fish waste that results in increased nitrates making the water cloudy. Changing the water in your tank is the only proven way to get rid of them and maintain a germ-free filter. Make sure the filter’s capacity is big enough for the size of your aquarium.

5. Too Much Leftover

Just give them as much food as you know they can eat. If you give them more food than they can eat, it will sink to the bottom of the aquarium and start to go bad, which will then break down into tiny pieces that will mix with water and make it look cloudy. Food that isn’t eaten also feeds bacteria and helps them grow.

6. Rotting Organic Materials

If the water in your tank is getting cloudy, check to see if there are any dead fish, snails, or plants that are rotting. Also, check the leaves of your aquarium plants to see if they are turning yellow because that usually means the plants will die soon. When these things break down, they can make the water cloudy.

7. Untreated Driftwood

Natural driftwood is a popular addition for aquarium enthusiasts who want to enhance the aesthetics of their tank while also providing their fish with a source of food. But driftwood usually leeches tannins into the tank and could make the tank cloudy.  The water begins as a pale yellow, but after some time has passed, it can become a much darker brown, like muddy water or an exotic sweet tea.

Why Is Your Aquarium Water Cloudy After a Filter Change?

Aquarium maintenance is important in keeping fish healthy and maintaining a clean, attractive environment. However, one common problem aquarium owners encounter is cloudy water after changing the filter. Here are 7 possible causes of this issue:

1. Abrupt Changes in Water Parameters

Fish can be sensitive to sudden changes in pH or temperature levels, which can cause cloudy aquarium water.

2. Improper Filter Set Up

If the filter isn’t properly set up, it won’t be able to effectively remove debris and particles from the aquarium water. This can cause the water to become cloudy.

3. Overfeeding

Overfeeding your fish can cause an increase in nitrates and phosphates in the water, which can cause cloudy water. You should only feed your fish as much as they can eat in a few minutes.

4. Insufficient Filtration

A poor filter system or inadequate filter media can lead to cloudy water. Many filters are not powerful enough for the size of the aquarium they’re used in and will not be able to keep up with the debris.

5. Bacteria Bloom 

A bacterial bloom is a rapid increase in the bacteria population, which can cause cloudy aquarium water. This is typically caused by an influx of organic waste from fish food or uneaten food that has gone bad.

6. Old Filter Media

If you haven’t changed the filter media in a while, it might be clogged with debris and particles. This can cause cloudy water and make it difficult for the filter to work properly.

7. Poor Water Quality

Poor water quality is one of the most common causes of cloudy aquarium water. This can be caused by a buildup of organic waste or chemicals, such as chlorine. It’s important to check your water quality regularly and maintain it at an optimal level.

Why Is Your Aquarium Water Brown and Cloudy

Brown and cloudy aquarium water can be a nuisance to any aquarist, but it’s important to understand the causes of this issue in order to find a solution. Here are seven potential reasons why your tank might be experiencing brown or cloudy waters.

1. Fish Waste

Fish excrete waste that accumulates on the bottom of the tank and breaks down over time, causing cloudy water and discoloration. To reduce this problem, do regular water changes and clean out debris from the substrate regularly with an aquarium siphon. 

2. Uncycled Tank 

If you have recently set up a new tank, then it is likely due to uncycled tank syndrome; as bacteria begin to break down organic material, such as fish waste and uneaten food, it can cause brown or cloudy water. To fix this issue, perform frequent partial water changes as well as add beneficial bacteria to the tank with a filter starter or similar product. 

3. Algae Bloom

Too much light or added nutrients in the aquarium can cause algae to bloom, leading to brown and cloudy waters. To reduce algae growth, limit lighting and cut back on feeding, as well as adding plants that consume extra nutrients present in the tank. 

4. Poor Filtration

If your filtration system is inadequate for your tank size, then it won’t be able to cope with all of the waste produced by your fish, resulting in cloudy and discolored water. To fix this issue, upgrade your filter or add additional filtration to your tank. 

5. Chemical Imbalance

Too much pH or ammonia in the water can cause cloudy and brown aquarium water. To rectify this situation, test your water parameters regularly and use a water conditioner to keep levels balanced. 

6. Decaying Plant Matter

If you have live plants in your tank, then dead leaves and other debris from decaying plants can lead to discoloration and cloudy water. Remove any dead plant material as soon as possible to avoid this problem. 

7. Mineral Deposits

Certain minerals present in tap water, such as iron, can cause crystals to form on the substrate and decorations over time, resulting in a brownish color. To reduce this issue, use a water conditioner to remove any minerals from your tap water before adding it to the tank. 

Aquarium Water Turned Yellow and Cloudy

Aquarium water is typically clear, but sometimes it can turn yellow or cloudy. While this may seem alarming, there are usually simple explanations for the discoloration. Here are seven common reasons why aquarium water has turned yellow or cloudy:

1. Algae Growth

Algae is a natural part of any healthy aquarium environment. However, too much of it can lead to discolored and cloudy water. Algae growth is caused by excessive sunlight, overfeeding and/or poor filtration. To reduce algae growth, make sure your tank isn’t getting too much direct sunlight exposure and practice good feeding practices (i.e., only feed your fish what they will eat in 3 minutes or less). 

2. Bacterial Bloom

Bacterial blooms are a natural occurrence in an aquarium and can cause water to become cloudy or yellow. These blooms typically happen when there is a sudden spike of nutrients in the water, such as after a water change or when fish waste accumulates in the tank. Do regular partial water changes and maintain a good filter to help prevent bacterial blooms. 

3. Ammonia Spike 

Too much ammonia in the water can cause it to become cloudy and yellow. Ammonia is produced by fish waste, uneaten food, decomposing plants, and other organic matter. Make sure you are doing regular water changes and that your filtration system is functioning properly to help keep ammonia levels in check.

4. Nitrate Spike

Similar to ammonia, nitrates can cause water to become cloudy and/or yellow if there are too high concentrations present in the tank. Monitor your nitrate levels regularly and make water changes as necessary to keep them within acceptable ranges. 

5. Not Enough Oxygen

Low oxygen levels in the water can cause it to become cloudy or yellow. Make sure your filter is working properly and that you have adequate aeration in the tank, either through an air pump or a bubbler. 

6. pH Imbalance

If the pH of your water is too high or low, it can cause it to become cloudy or yellow. Test your water regularly for pH levels and make adjustments as needed to keep them within the ideal range for your fish. 

7. Copper

Copper can be toxic to fish in high concentrations and will turn water cloudy and yellow or greenish-brown if present in the tank. Monitor copper levels regularly, especially if you are using a copper-based medication, and do water changes as necessary. 

Why Did Your Aquarium Go Cloudy Overnight

 Fish tank water can go cloudy overnight for many reasons. Although a cloudy aquarium may be worrisome, it’s not necessarily dangerous and can often be resolved with the right diagnosis and care. Here are five of the most common causes of cloudy aquarium water:

1. Overfeeding

Overfeeding your fish is one of the most common causes of cloudiness in tanks. When too much food is added to an aquarium, uneaten pieces break down into particles that become suspended in the water as waste, and bacteria feed on it. This suspended material makes aquarium water appear cloudy.

2. Bacterial Bloom 

Aquariums contain beneficial bacteria that help process ammonia and nitrates within the tank environment, but when these bacteria reproduce rapidly, they form a cloud of tiny particles that cause cloudy water. This is known as a bacterial bloom and can occur when an aquarium has been set up too quickly or if the environment is stressed.

3. Algae Growth

Excessive algae growth can also lead to cloudiness in an aquarium. The type of algae usually depends on the amount of sunlight and nutrients within the tank, with green algae being one of the most common types to cause cloudy water. 

4. Poor Filtration

Inadequate filtration systems can lead to cloudy aquarium water as they won’t be able to keep up with stabilizing the environment of your tank correctly. If you have recently changed or added a filter system make sure it is adequate for your tank size and the type of fish you have.

5. Improper Cleaning 

Poor cleaning practices can also cause cloudy aquarium water, particularly when using tap water to change out existing water. Tap water contains chlorine, which can kill off beneficial bacteria if it’s not properly treated before adding it to an aquarium. Instead, always use a dechlorinator or allow tap water to sit for 24 hours before using it in your tank. 

Why Is Your Aquarium Water White and Cloudy

Having clear and healthy aquarium water is essential for a good ecosystem in which your fish can thrive. Unfortunately, many aquarists have experienced white or cloudy aquarium water at some point. In this article, we’ll go over seven common causes of white or cloudy aquarium water and how to fix them.

1. Bacterial Bloom

A bacterial bloom is one of the most common causes of white or cloudy aquarium water. It occurs when bacteria in the tank multiply rapidly, often due to an increase in organic material such as uneaten food, deceased organisms, or excess waste from the fish themselves. 

2. Poor Filtration

If you don’t have a good filtration system in place, your water won’t be properly oxygenated, and particles of debris can build up. When the debris is not filtered out efficiently, it will create a cloudy appearance in the aquarium water. 

3. Too Much Light

Having too much light in your aquarium can cause algae blooms which will turn your water cloudy or white. Light is one of the main components for algae growth, so reducing the amount of light in your aquarium should help reduce any algae blooms.

4. Overfeeding 

If you’re overfeeding your fish, it can lead to uneaten food and excess waste in your tank that will make the water cloudy or white. You may notice a white film or milky substance on the surface of the water, which is a sign of overfeeding.

5. pH Imbalances

A pH imbalance can cause discoloration in your aquarium water, including cloudy or white water. The right pH should typically be between 6.5 and 8.0, depending on the species of fish in your tank.

6. Chemical Imbalances

Just like pH imbalances, chemical imbalances can lead to cloudy or white water in your aquarium. This happens when certain chemicals, such as nitrites, are at abnormally high levels.

7. Old Water

Aquarium water should be partially replaced every week to reduce the concentration of ammonia, nitrites, and other toxins that have built up in the tank. If you don’t do this, these toxins can cause cloudy or white water. 

How to Get Rid of White Cloudy Aquarium Water

White cloudy aquarium water can be an eyesore and a source of frustration for any fish keeper. Fortunately, there are several ways to clear it up quickly and easily. Here are 7 tips on how to get rid of white cloudy aquarium water:

1. Increase the Filtration

Increasing the filtration in your tank can help remove some of the suspended particles that cause cloudy water. Make sure you have a good filter and keep it clean by changing out or cleaning its media regularly.

2. Check Your Stocking Levels 

Overstocking tanks can lead to increased waste in the water, which can make your aquarium water cloudy when not removed properly by filtration or water changes. Make sure you’re stocking levels are appropriate for your tank size.

3. Change the Water

Performing regular water changes is one of the best ways to keep your aquarium clear and clean. Water changes help remove waste and debris that can make your water cloudy, as well as reduce nitrate levels.

4. Add Beneficial Bacteria

Adding beneficial bacteria to your tank will help break down organic materials that can cause cloudy water. Look for products containing live cultures of nitrifying bacteria specifically designed for aquariums. 

5. Use Chemical Filtration Media

Chemical filtration media, such as activated carbon or chemical resin, will help absorb some of the dissolved particles causing the cloudy appearance of your aquarium water. Make sure you rinse off any chemical filter media prior to use.

6. Adjust Your Lighting

If you’re using high-intensity lighting in your tank, it can cause an algae bloom that appears as cloudy water. Lowering the intensity of the light or supplementing it with a more natural spectrum of light may help clear up the cloudiness. 

7. Avoid Overfeeding

Overfeeding leads to increased waste in the tank and can cause cloudy water when not removed properly. Make sure you’re feeding only what your fish will consume within 1-2 minutes, twice per day at most. 

Is Cloudy Water Bad for Fish?

Cloudy water can be bad for fish for a number of reasons. First, it can reduce the amount of oxygen in the water, making it difficult for fish to breathe. Additionally, cloudy water can block out the sun, making it difficult for plants to photosynthesize and produce oxygen. 

Aside from diminishing the aesthetic value of your carefully crafted fish habitat, cloudy water in your aquarium may be an indication that the quality of the water in your tank is not up to par for your fish. There are many things that can make your fish tank cloudy, and most of them are bad for the fish. If it is not identified and remedied, your fish could become unhappy, stressed, or even ill.

Finally, cloudy water can impede visibility, making it difficult for fish to find food. As a result, cloudy water can create a stressful and dangerous environment for fish. If you notice your fish seem stressed or listless, it may be time to do a water change to help them thrive.


How Long Does It Take for Cloudy Aquarium Water to Clear?

Cloudy water will clear up in about a week. The more we tamper with the tank, the longer the cloudy water stays.

Why Is Aquarium Water Cloudy with No Fish?

Even if the tank is brand new and has no fish, the water will eventually get cloudy. When the water gets cloudy, the nitrogen cycle begins. This means that fish and other animals will be able to live in your aquarium in the future.

What’s the Fastest Way to Clear Cloudy Aquarium Water?

There are lots of ways you can remove cloudy water in your aquarium like adding activated carbon, either loose or in the form of carbon pads, to the filter. Adding activated carbon media or activated carbon pads to the filter will help clean the water and soak up the nutrients that feed the bacteria.

Does High Ph Cause Cloudy Water in An Aquarium?

A high pH does not directly cause cloudy water in an aquarium. Instead, it can be caused by high levels of dissolved substances, such as phosphates, silicates, or heavy metals which in turn makes the pH high. 

Can Low Ph Cause Cloudy Aquarium Water?

Algal bloom will happen in your aquarium if the pH is low. The water in your aquarium gets cloudy when there is an algal bloom.

Does Sand Make Aquarium Water Cloudy?

New gravel and sand will contain some dust. Water in the tank will become cloudy if gravel isn’t washed before being added.

Will Adding Live Plants to My Aquarium Make the Water Cloudy?

Aqueon claims that adding aquatic plants to an aquarium does not lead to cloudier water. Instead, the “good” bacteria and other microbes found on live plants actually help establish the biological balance in the aquarium by competing for nutrients and starving out microbes responsible for cloudy water.


Cloudy water is a common problem in aquariums. Algal bloom, incorrect pH, and inadequate aquarium maintenance are just a few of the many possible causes. Overfeeding, improper aquarium lighting g, and chemical filtration are all things you can do to keep this from happening. Depending on the cause, fish in an aquarium with cloudy water could also be in danger. Keeping the water in your aquarium crystal clear is easy when you know what makes the water cloudy.