This problem along with smelly or foamy water is caused by a high concentration of bacteria in the water. Uneaten fish food or fish waste in the water provides nourishment for bacteria, that are floating in the water, and feeding on the waste in the water. These bacteria often cause Signs of Stress and Disease in the fish. 1. Start by thoroughly cleaning your tank. 2. Change Some Water Every Day. Change some water every day. I recommend that you change 20% of the water. Changing more than 20% of the water in one day is risky to your fish. By changing some of the water, you'll remove some of the dissolved waste and begin to starve the bacteria. But don't get impatient and change too much water, because that can harm the fish. 3. Reduce the Amount of Food. Too much food often causes Cloudy Water, so reduce the amount of food and be sure your fish eat all the food that you feed them. Remove uneaten food after 10 minutes. 4. Add the Following Chemicals to Your Water. Aquarium Salt. The dose is on the box. Water Conditioner. The correct dose is on the bottle. Quick Cure. Add a half-dose as a preventative. Do not add any other chemicals or medications to the water. Add the Aquarium Salt just once, but repeat the AquaSafe and Quick Cure every day until the water clears. Be careful to use the correct doses of each chemical because more will not be better. All three of these items are available in most stores that sell pet fish. 5. If your Fish's Home has Gravel, get a handful of gravel from an established aquarium with healthy fish and sprinkle that gravel on top of the gravel that you already have. The beneficial bacteria that are living on the handful of gravel will quickly multiply to cover the surfaces of the rest of the gravel in your cloudy aquarium. The beneficial bacterial will digest the waste in your water, and the water will quickly clear. Where can you get a handful of gravel from an established aquarium with healthy fish? Often you can just go to a local fish store and ask for a handful of gravel, and they will give it to you. You might offer to pay. Ask them to get the gravel from an aquarium that has been trouble free. For example, you certainly wouldn't want to get gravel from an aquarium that recently had a case of the disease called ich. The fish store may also offer to sell you several different products that will solve your Cloudy Water problem. Just tell them that you'd like to try the handful of gravel first. 6. How to Avoid Cloudy, Foamy, or Smelly Water. Don't feed your fish more than they can eat. Learn to feed your fish so there isn't any uneaten food left over. Carefully watch your fish eat and then remove any uneaten food after 10 minutes. Be sure to clean your tank once a month and change 20% of the water twice a week. If you have an aquarium, it should have the correct type of filter that's clean and working properly. I recommend a power filter with a BIO-Wheel. The BIO-Wheel is very important. A layer of gravel 1/4-inch thick will help keep the water in a fish bowl clear. But aquariums with a bio-wheel filter don't need gravel. If you like the appearance of gravel, make sure it's only 1/4-inch thick. Always stir the gravel gently just before you change water.