Can You Add Fish To A Cloudy Tank? (How To Get Rid Of Cloudy Water?)

Cloudy water can be very problematic for many aquarium owners as it looks bad and sometimes takes time and effort to get rid of it. There can be numerous causes, like excess nutrients to the unwashed substrate behind cloudy water conditions.

Many aquarists come up with the question of whether they can put fish in a cloudy tank. So, Can you add fish to a cloudy tank? Let us find out.

Don’t add fish to a cloudy water tank as there can be numerous reasons behind cloudy water conditions, like a bacterial bloom and increased levels of chemicals in the water. Bacterial bloom can result in oxygen deficiency. Consider letting the tank water to get settle first and then add fish.

This article will discuss whether we can add fish to a cloudy tank, and also, we will discuss the reason, solution, and prevention for cloudy water. So, let us get into it.

Is it safe to put fish in a cloudy tank?

We don’t recommend adding fish to a cloudy water tank.

There can be numerous reasons for a cloudy tank condition.

If your tank has been cloudy immediately or after an hour of filling the tank, the gravel residue is the issue here.

Other reasons can be bacterial blossoms and algae bloom (If the tank is developing greenish color water.),

Now the causes can be too much debris, rotten plants, uneaten foods, and high nitrates.

All these reasons can harm your fish, and their health will be affected.

So, it is wise not to add fish to the cloudy tank and should wait for the tank to settle down first.

What are the reasons behind my tank having cloudy water?

If your tank has developed white or grayish water, then all these can be the reason behind such conditions:

  1. Gravel residue
  2. Bacterial bloom
  3. High-level dissolved chemicals.

Gravel Residue

If your tank develops cloudy water right after filling it or after some hours of filling it, the substrate is the issue.

An unwashed substrate is a primary reason for most tanks developing cloudy water.

Bacterial Bloom

Bacterial bloom is the sudden increase of bacterial colonies in the tank.

They develop so quickly that we can see them with our naked eye as the water gets cloudy.

It can be seen in the newly set up aquarium but can also occur in an aquarium with high nitrates and phosphates.

The nitrates and phosphates increase in the aquarium when the fish and plants die, and we don’t remove them from the tank for a long go.

Overfeeding will also play a major role in spiking such nutrients in the water.

High-Level Dissolved Chemicals.

If you have newly set up your tank and filled the tank with water, after some time, you notice cloudy water and gravel residue is not the issue, then dissolved chemicals are the cause.

Increased levels of phosphates, heavy metals, or silicates are the reason for cloudy water.

In such case, if you test your fish tank’s water, you will find that the pH level of your tank water will be high. 

If your tank has developed greenish water, algae are the reason for such an issue.

These all are the possible reason behind algae spikes in your fish tank:

  1. Spike of nitrate.
  2. Excess light in the fish tank
  3. Increased level of phosphates.
  4. Excessive nutrients in the water.

Also read: Purple Algae In Fish Tank?

Spike of nitrate

A Spike in nitrate is the common reason behind algae growth in a tank.

Nitrate usually rises because of excessive fish waste.

Overcrowding and overfeeding will elevate the nitrate level of your fish tank.

Excess light in the tank

The most common cause of algae growth in most tanks is too much light.

Placing the aquarium where there is a direct source of sunlight will result in algae growth in the tank.

Turning the artificial light on for too long will also promote algae growth.

Increased level of phosphates.

The phosphate sources in your fish tank are decayed fish food and the water itself.

The tap water you are using in your fish tank may have elevated phosphate.

In such cases, you have to change the water source and use RO water which you can easily find in pet stores. 

Or you can use the phosphate remover to eliminate the phosphate.

Feeding your fish with food that is lower in phosphate level and also providing limited food will prevent such issues.

Excessive nutrients in the water.

Excessive nutrients like phosphates and nitrates promote algae growth in a fish tank.

Reducing the level of such nutrients is necessary as not doing it will result in excess algae in your fish tank.

Performing a water change will help you get rid of such issues for a short period of time. 

You must eliminate the source of phosphate and nitrate to resolve this issue.

How long does it take for cloudy aquarium water to clear?

It entirely depends on the reason behind the cloudy water conditions.

If you have newly set up the tank, it can take up to 1-2 days for the tank to settle, and the cloudy water will cleat by itself.

Other factors like bacteria and algae bloom can take weeks to months to clear.

More water change and cleaning process will reduce the time and help clear the cloudy water quickly.

How can we clear cloudy aquarium water?

In case to clear the cloudy aquarium water, you must first find the reason behind it.

If you have newly set up your tank and filled the water, it is common to have cloudy water for some time as the heterotrophs and autotrophs bacteria are produced.

These all will settle down in time, and you will have clean water.

If the substrate is the reason for cloudy water right after filling the tank, then take out the water from the tank and rinse the gravel until the water runs clear.

If the bacterial bloom is the reason behind cloudy water, then perform all these things to get rid of it:

  1. Keep the tank super clean by vacuuming uneaten food, dead and decaying fish, and plants.
  2. Keep the substrate clean by using a gravel siphon.
  3. Perform a partial water change.
  4. Feed your fish in a quantity that they can finish eating in one to two minutes so that there is no decayed food left.

If you are not able to vacuum or siphon any uneaten food by vacuuming or performing a water change, you can use a flocculant to clear them away.

If algae are the reason behind cloudy water, then ensure all these things to clear the aquarium water:

  1. Don’t let the aquarium lights on for more than 8 hours a day.
  2. Remove the aquarium from a place if direct sunlight comes.
  3. Add live aquatic plants.
  4. Perform a 50% water change. 
  5. Treat the water using the API water conditioner to eliminate heavy metals, nitrates, ammonia, and nitrites.
  6. You can also use Seachem flourish excel carbon.

Performing a regular water change, avoiding overstocking and overfeeding, and treating the water with a water conditioner will help you prevent and get rid of cloudy water in most cases. 

How to prevent cloudy water in a tank?

Doing all these things will help you prevent cloudy water in your fish tank:

  1. Cycle your tank correctly.
  2. Ensure regular water changes.
  3. Go for the right type of substrate.
  4. Avoid overfeeding your fish.
  5. Avoid overcrowding your fish tank.
  6. Add live aquatic plants to your fish tank.

Cycle the tank correctly.

It is necessary to cycle the new tank to ensure a longer and healthier lifespan for the fish that will live inside that tank.

Cycling the tank will develop beneficial bacteria in your tank system, which will help you break down ammonia into nitrite into nitrates.

This process will take four to five weeks, and you can notice cloudy water during this process and also after this process for a few days.

Ensure regular water changes.

Performing a regular water change is necessary to keep the water clean.

Consider doing a water change of 30-35% weekly to maintain the water quality.

Doing a water change will help you remove the dirty water from the tank and replace it with clean water.

Make sure to treat the tap water with water conditioner while adding it to your fish tank, as it will help you eliminate chlorine, chloramine, ammonia, nitrites, and heavy metals from the tank.

We recommend using the API water conditioner to treat the water as it will help you to eliminate chlorine, chloramine, nitrite, ammonia, and heavy metals from the water.

Go for the right type of substrate.

Substrates are the primary reason for cloudy water in your fish tank.

If you have added a new substrate to your tank, it is common to have cloudy water for some time.

However, it will surely be a disaster if you don’t wash the substrate nicely before adding it to your tank.

Some substrates don’t have an epoxy coating, so it is necessary to wash the substrate before adding it to your fish tank to avoid cloudy water.

Also read: How Much Substrate For A 75-Gallon Tank?

Avoid overfeeding your fish.

Avoid overfeeding your fish to prevent cloudy water in your fish tank.

Overfeeding results in lots of fish waste and uneaten food in the tank, which good bacteria don’t get able to break down quickly.

The uneaten food will get decompose and will cause cloudy water.

To avoid overfeeding, feed your fish in a quantity that they can finish eating in one to two minutes.

If you are feeding them once a day, feed them in a quantity that they can finish eating in three to four minutes.

Also read: Can Goldfish Die From Overfeeding?

Avoid overcrowding your fish tank.

Having too much fish in your fish tank will produce too much fish waste.

Too much food waste can contribute to making the water cloudy due to dirty conditions. 

Also, an overcrowded tank will come with all these issues:

  1. An overcrowded tank will get dirty faster than regular.
  2. There will be a risk of ammonia poisoning in a crowded tank.
  3. Your fish will not be able to live and swim comfortably.
  4. There will be a risk of oxygen deficiency in an overcrowded tank.

Also read: How Many Guppies In A 20 Gallon Tank?

Add live aquatic plants.

Adding live aquatic plants will prevent cloudy water in your fish tank.

Plants will feed on the nutrients that other bacteria require and help eliminate the bacteria causing cloudy water.

Plants produce oxygen during the daytime, which helps in breaking down fish waste and uneaten food.

Plants help in clearing the water and preventing cloudy water conditions.

Also read: Do Cory Catfish Need Live Plants?


Don’t consider adding fish to a cloudy tank, as it can harm them.

The common reason for a cloudy fish tank is excessive feeding and uncleaned substrate.

Adding more fish will promote more waste and will not help eliminate the cloudy water.

Also, if you have newly set up your tank, let the cloudy water settle first, and then you can start stocking fish into it.

To perform a nitrogen cycle, you can avoid adding fish and consider adding small amounts of fish food every day until the ammonia breaks into nitrites.

Reference: Wikipedia, UKAPS

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