Why Is My Fish Tank Cloudy?

Published on March 25, 2017
Why Is My Fish Tank Cloudy?

What is the least enjoyable activity in aquascape?
I believe the majority of us will answer: water change.

Even for some of us, we have tried to change the water regularly, on time, without missing a single day throughout the year, yet we still find our aquarium in many occasions turns milky white cloudy.

If the paragraph above sounds familiar to you; then you have come to the right place!

This article will answer the question why our fish tanks sometimes or often turn cloudy.

reasons why your fish tank is cloudy

More fish, less space

People often imagine that just because they can afford to buy a huge tank, they have a free pass to place as many species of fish as they like.

Unfortunately, it does not always work like that.

Just as we humans require clean and unpolluted air to breathe abundantly, fish too, whether small or large, need a certain amount of water space to navigate freely.

And we all know that every fish needs something to eat, and at the end, fish will turn that food into various outputs. They can be the energy to swim, the nutrients to grow, and of course the feces.

The more fish live in the same tank, the more feces they will produce.

Some might ask: Ok... I do confess that I have too many fish in one tank, what should I do next?

The answer is simple. Move some fish to another aquarium, or if you don't want it, you can change the water more often than the "required" water change cycle.

Dirt and Debris

dirt and debris cloudy aquarium

The next commonest cause of a cloudy aquarium is dust and debris.

If you want to find your aquarium's dirt and debris, they can be found in sand or gravel (a.k.a substrate) in your aquarium.

It sinks at the base of the aquarium and is meant to enhance an ideal swimming environment for the fish. When the substrates mix with water in the aquarium, the water color changes and becomes unpleasant.

Filters are accidentally off

aquarium filter for cloudy aquarium

When setting up a new aquarium, what is the very first kit that you buy? Yes, that's right! Water filter.

If you ask any aquarist expert out there, to keep an aquarium healthy and clean, it is extremely recommended to keep your water filter on continuously without a break. 

Well, obviously you'll need to turn it off during the water change 😉

Besides, a water filter can help to filter out the feces and dirt out of the water flow; it contributes to keeping the "good" bacteria that lives in the water to stay alive.

How, though? It's simple; it helps to circulate the oxygen throughout the aquarium which then is consumed by the good-guy bacteria.

If let's say we fail to keep them alive. Finding these good bacterias dying is a good reason for your aquarium to turn cloudy.

Bacteria Blooms

Keeping aquarium ammonia under control and understanding the nitrate cycle is crucial to the tank's health.

If you would like to know the reasons, here are some:

  1. Decomposition of organic matter inside an aquarium is one way through which ammonia can enter the aquarium beside the ammonia produced by the fish themselves.
    FYI, proteins make up all living organisms, such as aquatic plants, microorganisms, and animals.
  2. Traces of proteins inside the tank are made up of soluble blocks called amino acids. A chemical reaction causes a break up into living organisms that end up releasing ammonia into the aquarium water, stimulating a hazy formation.
  3. The bacteria in your aquarium is not a bad thing. Indeed it's a necessary ingredient to maintain a healthy water ecosystem. The balance between the fish and the water in the aquarium is what keeps toxic chemicals inside the water under control.
  4. Unfortunately, life is not always one good sail, and something can happen to your tank to tip the scales of the bacteria colonies causing the population to explode with the availability of food.
  5. When the tank cycle begins, there are not enough bacteria in the filter to consume the ammonia produced by your fish. Bacteria will then accumulate in the main tank to summon sufficient force to absorb the ammonia. It is the free swimming bacteria attacking the ammonia that causes the water to look cloudy.
  6. If this happens to you, you need not panic. Fish are also not exposed to any danger since the bacteria are there for a good reason. To get rid of ammonia. It may look unsettling, and if you give it time the water will retain its clarity, but if the time has come to recycle the water, just go ahead and recycle the water.

Disturbing the Bacteria colony by Changing Water

Introducing medication to the aquarium can create a disturbance to the bacteria colony, causing the water to look cloudy.

A good example is methylene blue.

The bacteria colony can also be disturbed by environmental changes, for example, pH or temperature fluctuations.

When are trying to re-establish the bacteria colony; the water can turn cloudy.

Changing large amounts of water can cause a mini cycle which may result in the water turning cloudy. If you've just installed a new aquarium or you've just changed the water, it will just take a couple of hours for your tank equilibrium to get restored. And the cloudiness should disappear on its own after a few hours.

Overfeeding Your Fish

overfeeding aquarium fish

Feeding your fish too often and too much is the next reason why your aquarium turns cloudy.

Instructions on fish food containers will give directions about feeding several times per day. But you need to monitor how much is getting eaten, and how much is dropping to the bottom of the tank.

When ample portions of uneaten food are dropped they end up decaying, and this can cause the water to turn hazy.

With controlled feeding and frequent sucking out particles of unconsumed food will minimize pollution.

Some fish keepers compensate overstocking by over-filtering, which is a good thing. But the best management solution may just be to maintain the stock down to minimal levels.

Excessive Amounts of Algae

Excessive amounts of algae will gradually alter the hue of the water in your tank.

If you've owned an aquarium for some time, then you're familiar with algae. They voluntarily sprout up on the walls of your tank, and if not removed, can turn your tank into one messy algae bloom.

Algae survive on sunlight and nitrogen. A sudden surge in nitrogen emitted through fish waste can also cause an algae bloom. Algae are living organisms and influence the ecosystem just like plants or fish. If you leave algae unchecked for long inside your tank, it can change the balance of your tank.


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