What Does It Mean When My Aquarium Gets Foggy?

Having an aquarium full of fish is easier than having many other kinds of pets -- fish require less maintenance than a dog or a cat. Children and adults alike enjoy watching the fish swim around the tank. Though fish do not require a lot of day-to-day maintenance, certain problems can arise in an aquarium environment; foggy, cloudy or dirty water can accumulate and spread to the tank walls, causing distress to the fish and providing poor visibility. This common problem can usually be remedied using a few simple methods.

  1. Disturbance Debris

    • Slightly foggy water may occur after you stir up particulate matter in the water by replacing the gravel, adding a decoration or disrupting the tank in some way; after a few hours, however, the debris should settle at the bottom once again and/or be picked up by the filter. If the problem persists, purchase a clarifying liquid solution from your local pet store; this should remove the fogginess and return the water to its clear state.

    Algae Bloom

    • Multiple conditions both in and outside of your fish tank can cause foggy water. A green tint, indicates an excess of algae, also called "algae bloom." Algae growth is caused by too much artificial or natural (sun) light and poor water quality. Move the tank away from any windows and turn off the aquarium light or any lighting fixtures close to the tank. Clean the filter thoroughly, which should help remove the algae spores. Commercially available algaecides and UV filters may also be effective if the problem continues.

    Overfeeding and Decay

    • Follow the directions on the package when dropping fish food into the tank to avoid overfeeding; food that is not eaten will sink to the bottom and fester, giving the water a white, clouded appearance. This can also occur from other sources of bacteria development, such as dead fish or extra particles. Clean the filter and replace 20 percent of the tank water with new water to remove some of the build-up and dilute the old water with the new, recommends Aquarium Fish, a site that sells pet fish and provides advice on how to keep them (aquariumfish.net).

    Cleaning and Maintaining Your Tank

    • The key to avoiding foggy tank water is to keep your tank functioning properly. Clean your aquarium regularly, removing 15 to 20 percent of the water at least once per week. Use an aquarium vacuum to remove any debris on the sides and bottom of the tank. Check pH and other chemical levels in the tank regularly. Always provide adequate filtration in your tank to keep your fish healthy and the environment fresh. For certain, more drastic, procedures you may have to remove the fish from the tank.