What Makes Aquarium Water Cloudy?

Those who keep aquariums might experience cloudy water in the tank. The coloration may be green, yellow, brown, silver or white depending on the cause. The cloudiness might occur during the first, middle or latter part of filling the tank, sometimes within the first few minutes. Cloudy water can be bad for fish, especially if it is caused by increased ammonia and nitrite levels, which can be lethal.

  1. Most Common Causes

    • Uneaten food, fish excrement and decaying plants may cause water cloudiness because bacteria develops in more than the normal volumes. When the aquarium is placed in direct sunlight, algal bloom might develop due to increased photosynthesis. Check the tank's location and the color of the cloudiness. Algal growth is greenish. You may also be over-feeding the fish: algae grows on fish waste and uneaten food.

      Too many fish produce a lot of waste, which increases bacterial action and produces cloudiness. A solution is to thin out the number of fish or change the tank's water more often. Water changes should occur weekly or bi-weekly, depending on the size of the tank and water test results. Sand, substrates, decorations or plants that have not been washed thoroughly may retain some substances, like dirt, particles or chalk, that cause the cloudiness. Some rocks, corals or shells also deteriorate in or react to the altered pH environments, releasing substances that turn the water cloudy white or grayish.

    Leaching Wood

    • Wood decorations, such as driftwood, might leach tannin into the water causing a brownish or yellowish cloudiness. Although tannin can cause cloudiness, it can also be beneficial by improving the immune systems of the fish and induce spawning. Depending on the species of fish, some, such as tetras and catfish, that spawn in the spring are positively affected by this phenomenon.

    Chemical Additives

    • Chemicals, such as dechlorinators and fish health tonics, added to the water might react with other substances already in the tank to produce the cloudiness. The paint in some decorations may also generate cloudiness, especially if one is peeling or dissolving due to age or a chemical reaction to something in the water. The presence of chemical substances, such as phosphates, heavy metals or silicates, can cause cloudiness in the water. This excess cloudiness can be reduced either by filtration or changing the water frequently.

    Bubbles

    • When filling the tank with water for the first time or in changing the load, minute bubbles may form that cloud it. The cloudiness appears silvery or white--sometimes grayish--- and should disappear usually after few minutes or sometimes hours, when the air in the bubbles have dissolved into the water or the bubbles have risen to the surface and burst.

    Ammonia

    • Water that hasn't been changed recently can house high ammonia levels that can cause cloudiness or discolored water. Check your water with an ammonia test strip or test tube kit to check your ammonia levels. Optimal levels should be 0 parts per million of ammonia. If your tank has increased levels of ammonia, a 50-percent water change should be done as a spike in ammonia can contribute to cloudiness and is harmful to fish and other organisms.