How to Clear Aquarium Cloudy Water

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by Jason Matthews


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Did you know there is no single cause for cloudy aquarium water? Cloudiness in an aquarium can be a baffling phenomenon as it deters you from thoroughly enjoying your beautiful fish tank. If you wish to comprehend why your aquarium may look hazy, keep intact as we explore possible reasons and how to clear up the cloudiness.

To clear up cloudiness in aquarium water, perform a 25% partial water change to dilute dissolved waste and chemicals in the water. Alternatively, clean the gravel using a gravel vacuum to remove fish waste and decaying matter. More so, other elements that could aid in fixing cloudy aquarium water include; overfeeding your fish, and overstocking.

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Understanding the leading cause of murkiness in an aquarium enhances the overall success in clearing exercise. Murky aquarium water could portray symptoms of more significant hurdles. Scroll below for more comprehensive scrutiny regarding how to clear cloudiness in aquarium water.

How to Deal with Causatives for Cloudy Aquarium Water

Bacterial Bloom

The bacterial bloom issue looks like diluted milk with almost no visible particles. It arises from decaying food and fish waste, which provide a rich source of nutrients for bacteria to generate. Mainly, bacterial bloom emerges when a new tank hasn’t been appropriately cycled, or a massive water change results in a mini-cycle; thus, bacteria re-population.

Bacteria in an aquarium is imperative in breaking down waste and maintaining healthy water conditions. When bacteria colonies fail to get the job done, waste builds up and the bacterial population rises with the abundance of food.

Clearing up a Bacterial Bloom

  • For a new aquarium or after performing a significant water change, the cloudiness clears up on its own in a few days as the tank comes in balance.
  • If the bacterial bloom results from excess waste matter accumulation, undertake a partial water change integrating your gravel vacuum. Regular partial water changes aids in diluting harmful waste chemicals plus keeping aquarium water healthy.


overfeeding can result in cloudy water

Water cloudiness can be a result of feeding your fish too much or too often. The cloudy nature may be due to food particles dissolved in the water. Uneaten food decays can cloud the water.

As much as it’s fine to feed your fish multiple times a day, ensure you get to know how much your fish are eating. The handle can take place in both large and small aquarium tanks.

Remedy for cloudy water due to overfeeding

  • Perform a partial water change and vacuum the gravel to clean up the aquarium and make the tank safer for your fish.
  • Re-evaluate the feeding schedule to avoid overfeeding and wastage. For instance, feed once per day and include one fasting day per week—this aid in keeping your tank cleaner.


overstocking in aquarium

Overstocked aquariums bring about behavioral clashes, stress for the fish, and a toxic environment, resulting in cloudy aquarium water. Too much fish in the little ecosystem interferes with the filter systems and microorganisms that help to break down waste.

The enclosed aquarium ecosystem is designed to support a specific number of fish life; therefore, the balance could get out of hand when overstocked.

Related article: How many fish you can have in a 3 gallon fish tank

Eliminating cloudy water in an overstocked aquarium

  • Keep your fish stock down at a level that the aquarium can maintain. Find a way to re-home some of the excess fish
  • Over-filter and keep a heavily planted tank
  • Vacuum the gravel and carry out a water change

Algae Bloom/ Green Water

The algae organisms grow on the sides of the aquarium, and if assumed, they can turn your water into a green mess. The algae bloom appears as a greenish hue. Algae development in an aquarium thrives due to the presence of a high amount of nitrogen and sunlight.

Algae bloom can’t be cleared by fine filter floss or massive water changes.

Related article: How to prevent algae in fish tanks

How to get rid of aquarium water after an algae bloom

  • Perform a water change and move your tank to where sunlight won’t help algae thrive.
  • Blackout the entire aquarium or use a UV sterilizer

Particles in the water

Specks/ particles in the water lead to cloudiness. The particles arise from a dusty substrate or other debris. When setting up a new aquarium, tiny bits of a substrate may float into the water column. In addition, when a filter gets full, it can’t collect more particles from the water.

How to clear up cloudiness in an aquarium with particles

  • Set a regular schedule for tank maintenance to remove excess waste
  • Carry out multiple significant water changes and vacuum the substrate using an aquarium siphon
  • Thoroughly rinse the substrate until all the silt is washed away
  • Clean the filter once every month

Why Is My Fish Tank Cloudy after Water Change

Cloudy watercolour could signify bacteria bloom which usually happens during the Nitrogen cycle cycling process, especially after a large water change. An aquarium may experience ‘new tank syndrome,’ which occurs upon the set up of a new aquarium or after carrying out a large water change.

Cloudy water in a new aquarium is a natural phenomenon as part of the system’s normal biological cycle. This results mainly from fluctuations in the nitrogen cycle, increase in water temperature, and release of gases in solution.

50% water change could depict cloudiness in an aquarium, but restarting the cycle could help overcome the murkiness. In addition, change the filter cartridge regularly to aid in clearing the cloudiness. Too much water change interferes with healthy microorganisms in the aquarium.

If the water is cloudy after filling the tank, drain the tank and rinse the gravel until the water turns clear.

Should I add live plants or beneficial bacteria?

Aquarium requires an excellent biological balance. Live plants feature good bacteria and microbes on them, which aid in establishing perfect natural balance. The live plants compete for nutrients hence starving out microbes that promote cloudy water.

Live plants are beneficial in an aquarium as they produce oxygen, which aids in the breakdown of fish waste and uneaten food. This is crucial in clearing the water.

Should I change the water more often?

Generally, regular partial water changes are suitable actions to help clear cloudiness. Aquarists should embrace the water change concept to deter severe fogginess within the aquarium.


Jason Matthews

My name is Jason Matthews, and welcome to my website. When other kids were bragging about how their dog could sit and roll over, I was bragging about my latest Betta Fish and the cool sea castle I just added to his aquarium. 

Jason aquariume

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