Causes of Cloudy Water in a Tropical Fish Tank

Whether you are a new aquarium owner or a seasoned veteran, a tank with cloudy water can be disheartening. Cloudy water can occur for many reasons, but with some basic knowledge, you can easily treat the problem and restore your tank to crystal clear water.

  1. Debris From Substrate

    • If you are experiencing cloudy water in the first few days after setting up your aquarium or after adding new substrate, such as sand or gravel, your cloudy water is likely a result of debris from the substrate. This can easily be avoided by thoroughly cleaning the substrate before adding it to your tank. The easiest way to do this is to place half of it into a bucket at a time and run clean water over it. Drain the bucket and continue to repeat the rinsing and draining process until the water runs clear. Any cloudiness that results from substrate will remedy itself in a few days by either being pulled out by the filter or settling to the bottom of the tank.

    Bacterial Bloom

    • Bacterial bloom usually presents itself as a white or grey haze. Often it occurs after you set up a new tank, however, it can also occur is established tanks. Cloudy water caused by bacterial bloom will resolve itself after a period of time, but you can help it along by performing a 20 percent water change. To avoid bacterial bloom, you should avoid overfeeding your fish and remove uneaten food from the tank since excess waste can make it worse. Luckily, it is not harmful to your fish.

    Chemical Imbalance

    • A chemical imbalance in your tank can cause a grey-white cloudiness in the water. It is often caused by hard water or too many additives in your tank. Limit your use of chemicals to dechlorintors and conditioners, if at all possible. Conditioners can help relive cloudiness caused by chemicals. Another important step is to change your tank's water regularly.

    Algae

    • If the cloudy water in your tank has a green hue to it, this is caused by algae growth. One of the easiest ways to combat algae growth is to make sure your tank is set up out of direct sunlight, since sunlight encourages it to grow. Also, do not leave your tank lighting on for more than 12 hours a day. Regular partial water changes can also help minimize algae. If you have an extreme problem with algae, try doing a water change of 30 to 40 percent every three days to help clear up the problem or install a ultra-violet sterilizer in your filtration system.

    Yellow Clouds

    • It is common to experience a yellow-hued cloudiness in tanks that contain driftwood. This is because of organic carbons presenting themselves in the tank. Yellow cloudiness can also occur due to the waste from the fish or when plants decay. If you believe the cloudiness is caused by the addition of new driftwood to the tank, give it a few days and the cloudiness should resolve itself. Use a filter with activated charcoal to help clear up the cloudiness and change the carbon filter at least every two months. Partial water changes can also help clear it up.