Why is my aquarium water cloudy

Why is my aquarium water cloudy?

Aquarium becomes cloudy due to various reasons, it could be yellowish due to ammonia spike, greenish due to algae bloom and others.


We will understand the reasons why the aquarium water becomes cloudy; it could be due to varieties of factors and we will look them in detail. If you are a new comer to the aquarium hobby you may have this question and probably looking answers for it so please read carefully and let us know if you have facing some other issues other than the ones we have highlighted.

Is there a problem with your source water?

The source water could be well water, city water or others and the water could be muddy or cloudy. Start using a simple water to remove the dust from the water using mechanical filtration so water becomes clear.

If you want to invest in advanced filtration, you can also use ADA NA water filter which can remove dust as well heavy chemicals since it has active carbon to remove harmful chemicals.

Issue with the sand or substrate used in the aquarium?

If you are using river sand or silicate sand, it will cause the water to be cloudy. Always rinse the water 3 or 4 times then use it in the aquarium.

If you are using planted aquarium you are probably using good aqua soil, please don’t wash them as contain good nutrients. When are filling the water in the aquarium please add it slowly so that the soil is not disturbed which will prevent water to be cloudy. If gets cloudy initially leave for couple of hours and check how it is, if it still cloudy change the water. Then set the filter to be turned on and leave the tank for a day and water will be clear in after 24 hours.

Water becomes yellowish?

Water becomes yellowish due to ammonia spikes either due to fish poop or excess food in the water. The water becomes yellowish and it is very harmful to the fish, change the water immediately to control the ammonia spikes.

The permanent solution is to get good biological media in your filter which will help to convert your ammonia to nitrite and nitrate.

If it’s a new tank then it will take time to cycle the tank so give 3 weeks to cycle the tank fully and then introduce the fish.

Water is Greenish in colour?

If the aquarium is kept closer to a window, then it will cause algae bloom which is green colour and your water becomes green. You might have generally seen in ponds or stagnated pools of water where the algae grows. The best way to control it is to put a curtain if your tank is near to a window or put a shade cloth or some cover over pond to control the algae.

If there is a little bit algae it is always good as it will be a source of food for your fish and for your bottom dwellers or algae eaters, we always have to keep this in check and avoid getting this out of control.

Water has a brownish colour?

If the aquarium has a brownish tinge mostly likely this is caused due to the wood releasing tannins into the water. Most of the newly introduced wood in the tank will release some kind of tannins.

If you want to use any new wood in your aquarium you can soak the wood externally in a tank or bucket of water for 2 to 3 weeks before you use it for your aquarium.

This is generally seen in blackwater aquariums. If you are using Indian Almond leaf or its extract it will also release tannins into the water and this will generally lower the PH so this is good for fishes which require less PH.


Whenever you see your fish tank is cloudy don’t get alarmed just try to find the root cause to the problem and start eliminating the above issues we have highlighted and this will help you find the solution to cloudiness issue.

Tip: Whenever you are filling the aquarium always fill the water slowly, introduce a small ceramic plate and place it at the bottom and the water should be falling slowly on this plate so that you soil or sand don’t get disturbed. This will help in preventing cloudiness to your tank. Hope this helps.

If you have any doubts or queries, please get in touch with me at




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