Cloudy Water in Fish Tank Solutions and Fixes

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Wondering why the water in your fish tank looks dirty and cloudy, even when you clean it regularly?

Trying to find hacks, fixes, or cloudy water in fish tank solutions? You’re in the right place.

Here, we’ll walk you through the possible reasons and provide you with tried and tested fixes.

Cloudy Water in Fish Tank Solutions

The first step towards arriving at cloudy water in fish tank solutions is identifying what color the water is taking.

A variety of factors usually cause murky water, and these reasons manifest through the water’s color.

Cloudy water in fish tanks can take on a whitish, greenish, or yellowish tone, and your approach to clearing the water depends precisely on this color.

White or Gray Cloudy Water

Notice a whitish or grayish hue on your tank’s water? Here’s what might be causing it:

Unwashed Substrate

If the water turns white or grayish an hour or two after filling the tank, your likely culprit is unwashed substrate or gravel can cause this cloudy water in fish tank.

Substrates and gravel contain fine, dust-like specks, which can separate and float around when placed underwater, causing this cloudy water in fish tank problem.


Thankfully, this problem isn’t too difficult to fix.

If you have a filter that uses fine mechanical media, you can simply wait until it traps the dust floating around.

The dust can also simply settle on the floor of your tank, making the water clearer, later on, ending the cloudy water in fish tank problem.

However, if you want to get rid of cloudy water in fish tank as soon as possible, you can opt to drain your tank, rinse the gravel, and check if the water will run clear.

High Levels of Dissolved Particles

If, after washing the gravel, you still find the water cloudy, perhaps you’re dealing with a high level of dissolved particles, such as phosphates or heavy metals.

A quick pH test can easily determine this.

Water that is high in dissolved particles will be alkaline or have a high pH.


In this case, all you need to do is to treat the water with conditioners.

Alternatively, you can use reverse osmosis water to fix this problem.

Bacterial Blossom

If water doesn’t turn murky immediately but still takes on a whitish or grayish hue, the cloudy water in fish tank problem is perhaps bacterial blossom.

This typically appears after a few weeks or months.

Excess food and decaying plants can contribute to making the water cloudy.

However, it usually takes some time (around several months) for a new aquarium to establish bacterial colonies that can remove waste from the water.

This is how aquariums running for a longer time resolve the hazy tint it takes on from its initial few months.


Since it resolves itself in time, you really won’t have to do anything to fix a bacterial bloom.

This is a normal occurrence when you’re cycling the water you use.

However, if you’re not cycling your tank and this still happens, check the level of ammonia or nitrites in the water.

cloudy water in fish tank solutions and fixes

Green Cloudy Water

Only one thing normally causes green water—algae growth.

Multiple factors can facilitate algae growth in your fish tank, and figuring out which one can help you curb algae growth quickly and easily.

Here’s what to watch out for:

Direct Sunlight

Directly exposing the tank to sunlight can facilitate algae growth.

If you leave the lights on for too long, this can also cause too much algae.


The good news is that this is the easiest problem to resolve.

All you have to do is place the aquarium in a spot where direct sunlight can’t reach it.

Additionally, you may want to reduce how long you keep the lights on to ensure algae won’t proliferate in the tank.

Excess Nitrates and Phosphates

High levels of nitrates and phosphates in the water are conducive to algae growth.

Although a water cycle can clean the water temporarily, this won’t address the cause of the problem.

The result?

Algae will continue growing in the tank despite regular water changes because of the excess nutrients.


Phosphates come from decaying matter (such as fish food) or your water source.

On the other hand, nitrate levels rise over time, as they are a major byproduct of fish waste.

To resolve these, check possible sources and cut down on what’s causing nitrate or phosphate levels to rise.

You can opt to reduce the amount of food you give your fish or switch to a brand with lower phosphate content.

It’s also a good idea to check your water source and determine if it has high phosphate levels.

If so, you can use reverse osmosis water or invest in a phosphate remover to treat the water.

If nitrates are the problem, regularly changing the water can do the trick.

Additionally, consider checking your filter and ensuring it’s kept clean. 

Yellow or Brown Cloudy Water

If your water has a brown or yellowish tinge, chances are, the driftwood inside the tank is releasing tannin, a form of brown dye.

Driftwood, along with other kinds of wood, leaves, and seed pods, releases tannin when soaked in water over a long period.


Different kinds of driftwood release different concentrations of tannins.

You can remedy this by pre-soaking the wood before placing it in your aquarium.

If it has already stained your tank, simply remove it and soak it some more before placing it back in.

You can also change the water or use a carbon filter to remove the color.


When it comes to solving cloudy aquarium water, the first step will almost always be figuring out the root cause.

Knowing these reasons will allow you to resolve and prevent cloudy water in your fish tank in the future.

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