Will A Filter Clear Cloudy Water in A Fish Tank?

You and your favorite water pets have a great relationship. You feed them, you make sure they have plenty of space to swim about, and you have all the best tank plants for them to hide behind. But one day, you see the water is murkier than either of you prefer.

Will a filter clear cloudy water in a fish tank? To a certain extent, a filter can help in clearing up cloudy tank water. However, this is typically not the only solution and should be done in tandem with other tasks to get your water back to a nice and clear state. If you have a brand new tank, changing the filter will have no effect.

No matter how little or how much experience you have, any fish owner will likely encounter a hazy tank from time to time. Although unsightly, this is a problem that is typically easily fixed with a little patience and some close investigation of its source. Continue reading to understand what cloudy water consists of, how filters can assist in ridding your tank of murky water, and other ways to combat this tank issue. 

What Exactly is Cloudy Water in Your Fish Tank?

You finally got your chance to set up your own aquarium. You have the perfect tank, fantastic lighting to see all the beautiful fish you have selected to go within, you were able to find beautiful plants to be placed all throughout, but after a few days, weeks, or months, the water begins to go from perfectly clear to perfectly cloudy.

You have done everything right as far as you know, so what on earth even is this new murky scene? Cloudy aquarium water is something that can appear overnight. It is a swift ruiner of tanks and leaves owners puzzled as to how it got there as well as how to fix it. 

Cloudy water is a bit more complex than you would think. It is the expansion of microscopic life which consists of different bacteria, protozoa, and micrometazoans. These little guys vary from tank to tank due to what fish are present, what food is available, and what microscopic predators are present.

You need those microscopic predators to keep bacteria at bay. However, when you add water to your aquarium it contains chlorine that works to kill any microscopic life that is present within it. Because of this, those negative life-forms are able to grow in abundance and take over the water in your aquarium.

Fish food can accelerate the production of these life forms due to the waste output that fish produce because of it as well as uneaten food in the tank. Both of these then become food sources for the bacteria and they continue to live their best life in your now overtaken aquarium water. 

It may seem like there would be no end in sight at this point, but this is where your filter is able to step in and do its work. Although usually not a complete solution, the filter will be able to take its own role in getting your water restored and getting your fish visibility back to where it needs to be. After all, no one likes to swim in fog. 

How Filters Help Clear Cloudy Water in Your Fish Tank

Any aquarium owner knows that a filter is one of the most essential components to keeping your fish’s environment clean and free of harmful bacteria. No matter how small this little device is, when the filter begins to fail or needs a quick replacement, the difference in your water is easily seen. 

Whether your water is green or cloudy, a filter can help to get the water back to its previous glory with only minimal work from you.  Although people may know the importance of a filter, maintenance of the filter is a task that is sometimes overlooked amid all the other to-do’s when it comes to aquarium care. 

If you think simply of the waste that your fish produce, this is pollutant enough to realize the necessity of a properly working filter. But even more than cleaning fish waste, there are all kinds of excess food, nasty chemicals, and decaying matter that needs to be removed. 

The filter helps to take all of this out, but if you have a filter that is working on its very last breath, it is of no use to you once your water has gotten cloudy. Be sure to remove the old filter and replace it with a new one so that it is capable of building up good bacteria that help filter through all the crud that is within your waters murky mess.

A filter can make or break the health of your aquarium and is a necessary focus when trying to get your cloudy water cleaned up.

Other Ways to Get Rid of Cloudy Water in Your Fish Tank

Now you know that the filter is a key player when it comes to keeping your water nice and clear, but it can also help to get rid of the nasty cloudiness that can sometimes pop up without warning.

Sometimes changing your filter is not the only thing needed to get your water back to the way it was. Because of this, there are a few other steps you can take to make sure your water gets and remains clean in your fish tank. 

  1. Let Your Aquarium Work Its Problems Out 
  2. Give it Good Bacteria 
  3. Change the Water 
  4. Feed Only What Fish Need

Let Your Aquarium Work Its Problems Out

Sometimes your greatest tool is time. As you know, aquariums are full of all different sorts of living organisms and sometimes these organisms get a bit out of balance. Especially true for new aquariums, sometimes these organisms need time to work their differences out and settle into a more utopian state.

This establishment is essential in creating a hard-working bacteria colony that will help to maintain the health of your aquarium’s environment. Keeping this understanding in mind, give your aquarium a little time to acclimate itself.

Try to withhold from adding chemicals, immediately changing the water, or getting a new type of filter. All of this can cause even more disbalance in your tank and inflate the problem even more. For a new tank, cloudy water can even be something as simple as rocks that have not been washed properly. Give your water a bit of time and then go forward with other solutions.

Give It Good Bacteria

Although there are bad bacteria, there is also good and your aquarium needs plenty of it. There are so many options that help in supplying the necessary bacteria that your aquarium needs to keep the fish and the water healthy. 

There are prepackaged bacterial cultures you can purchase and simply add to the tank which makes it super easy to get your water where it needs to be bacteria wise without having to measure the different components yourself.

For those who plan to add rocks to their aquariums, there is gravel you can purchase that is actually pre-seeded with bacteria and other types of healthy life-forms that will get your water working right off the bat. 

Along with gravel, live plants instead of plastic are a great option for your aquarium. Live plants are great because they are a natural filter but they are also covered from head to toe with the microorganisms that your tank needs. 

Change the Water

This may seem like a no-brainer, but your water must be changed once your tank has established itself so that the environment does not begin to turn on itself. Now, this does not mean that you need to figure out a way to get rid of every last drop in your tank.

This could actually mean even more trouble because you would be getting rid of established bacteria that are needed to keep the waters’ environment going strong. 

You want to get new water into your tank as often as you can to keep any harmful bacteria from breeding and running amuck. For those tanks that are not too crowded with fish, changing about 25 percent of the water at a time will do the trick.

Do this every week at the least and every two weeks if you really want to push the envelope. Clean water means happy fish and happy fish mean a happy fish keeper!

Feed Only What Fish Need

So many times, fish owners think that their water pets need more food than they actually do. This will result in the fish not consuming what they are given and keeps uneaten food within the tank. 

This creates a food supply for bad bacteria and will keep your water from staying clear. Fish only need a light feed once a day, so don’t guilt yourself when you find yourself eating dinner and your fish is without. They do not need the calories and your tank will thank you! 


So, to sum it all up, yes, a filter will clear cloudy water in a fish tank as it removes microscopic life forms and harmful bacteria that cloud up the otherwise clear water. But, you can also get rid of cloudy water in your fish tank by letting your aquarium work its own problems out, adding good bacteria, changing the water, and feeding only what the fish need to survive.


I'm passionate about fish pets and love sharing everything I learn about them.

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