Shopping Cart

Your cart is empty

Continue Shopping

Why Is My Fish Tank Cloudy and How to Fix It

Owning an aquarium has many benefits, such as stress relief, cure of diseases and beauty to your home. But a cloudy fish tank can be annoying since it will spoil the aesthetic as well as affect the health of your fish.

Today, we are going to figure out the reason why the fish tank gets cloudy and how to fix it. But before that, please take a look at your tank and see what color is it.

There are three types of cloudy fish tanks in this article, the white/milky fish tank, the green fish tank and the yellow/brown fish tank. You can find the causes and measures corresponding to the color of your tank.


White/milky fish tank

First, we’ll talk about the white/milky fish tank. This cloudy fish tank is caused by unwashed substrate, untreated water and bacterial bloom. You may don’t take it seriously or even ignore it at the beginning, but when things get worse, you’ll find it troublesome. So take measures when you notice the tendency that your tank becomes white/milky.

White/Milky fish tank

1. Add unwashed substrate to your tank

When building up a new fish tank, we’ll suggest you wash the substrate (if you plan to add one to your tank). The newly bought substrate is covered with some tiny dust that you can not see, when you put it in a bucket and use water to rinse it, you’ll get some dirty water, which looks white or milky. If you skip this step before putting the substrate in your tank, the dirty water will stay in your fish tank and lead to a cloudy fish tank.

How to get rid of it

Normally, after a few days, the dust will sink to the substrate and your tank will become clear. But the dust is light and removable. Every time your fish swim or you add some decorations or equipment to your fish tank, you’ll make water current, resulting in cloudy water again.

Therefore, you’d better take some steps to ameliorate this situation. Things you can do include the following:


2. Use untreated water for your tank

In our former blog, we talked about what kind of water to use for fish tanks and how to dechlorinate tap water. I think you’ve already known tap water or other untreated water can not be used for fish tanks, and if you use it, you’ll bring the cloud to your fish tank. That’s because this kind of water contains many metals, silicates, or phosphates. So if you have cleaned your substrate, you can check if the water you use is not proper.

How to get rid of it

Getting rid of cloudy water caused by untreated water is simple, you just need to add some water conditioner to your tank and wait for some hours. Be sure there is no fish in your tank since the conditioner may hurt them.

As for how much conditioner should you add, I can not give you an accurate answer as I don’t know your condition. Usually, the experts recommend a 0.5 ml ( 10 drops)water conditioner for a one-gallon fish tank, you can use it as a reference.


3. Bacteria bloom

Now we come to the third cause of white/milky fish tank-bacteria bloom. It happens most in a newly established tank, after a water change or replacement of filter media. In these situations, there are few beneficial bacteria in your fish tank, and the bad bacteria will bloom quickly if there is much waste for them. But things will get better when your beneficial bacteria begin to come into play.

How to get rid of it

Overfeeding, overcrowding, inefficient filter and other reasons that will lead to too much waste in the fish tank are the causes, so we should get rid of this situation according them.

  • If it is a newly established tank, just let it go. The phenomenon will disappear after a few days.
  • Never overfeed your fish and feed your fish properly.
  • Arrange your fish tank reasonably, do not overstock your fish tank.
  • Add some beneficial bacteria to your fish tank.
  • Do not wash your filter when you do a water change or clean your fish tank.
  • Do not over-clean your fish tank.
  • Change the right amount of water regularly.


Green fish tank

I believe you all know algae, which is the food for most livestock in your fish tank. However, algae will cause cloudy fish tanks as well. If you find your fish tank green, the only cause you should check is excessive algae.

Green fish tank

How to get rid of it

To know how to get rid of algae, you should know why there are algae in your tank. There are many types of algae and each of them is caused by different reasons, and the measures to deal with them are different. You can reach for the article “How to get rid of algae in the fish tank” to better solve this problem.


Yellow/brown fish tank

If your tank looks yellow or grown, the reason should be excessive tannins. Tannins are caused by fish waste, decay plants and driftwood.

Tannins do have some benefits to your fish tank. They can lower the pH level, help fish breed and prevent the growth of algae. So if the tannins do not influence the water parameters and the health of your fish, I’ll recommend you ignore the cloudy fish tank.

Yellow/Brown fish tank

How to get rid of it

But if they are harming your fish and contaminate the water, you should remove them immediately. Methods you can use include:

  • Use activated carbon
  • Soak or boil the driftwood before using
  • Remove the fish waste in time
  • Use chemicals to neutralize the acid
  • Do a regular water change



After reading this passage, you’ll find if there is only one answer to the question of how to fix a cloudy fish tank, it should be good tank maintenance. Once you pay attention to it, test the water daily, remove uneaten food, do a regular water change, and check your equipment, you’ll easily get away from a cloudy fish tank.

Comments (0)

Leave a comment