All I want is an aquarium with clear water. Period. I just set up a 10 gallon tank with a brand spankin' new Whisper Filter rated for 15-20 gallons. I have the inch + of rocks (the larger ones) that was recommended. I treated the water with 2 teaspoons of StressCote and let the filter run for three days before introducing my ONE fish--a goldfish-looking thing that I don't think is actually a goldfish. I feed this fish MAYBE 3-4 small goldfish flakes of a day and he's been thriving on this since his debut in our family last November. He had been in a woefully inadequate 1 gallon jobbie until I could figure out if I could keep him alive. I have two smallish plastic plants and the aquarium is not in any sun at all. It's a steady 65-68 degrees in the room the tank's in. Well, three days later, the water's already getting cloudy. What do I do, or what am I doing wrong?