What can make a freshwater fish tank cloudy?
Another cause of cloudy water, and one which I have experienced myself, is free floating Algal blooms, literally algae floating about. It can occur when there is a lot of sunlight shining through or into the tank, along with high nitrate levels. Nitrate levels can be elevated in tap water, as well as by excess fish food and waste. Try a 25% water change, a bacterial supplement, perhaps reduce the quantity of food you feed the fish, and get your water checked for Nitrate and Ammonia. In the UK most Aquatic shops will test your tank water for a small fee, otherwise you can buy a home test kit, but these can contain potentially harmful chemicals.
