I got a fish tank a couple of weeks ago and I put it on top of my dresser by the bathroom door. I did everything that I was supposed to do according to the booklet that I gained. I did not want to kill the fish as soon as I brought them home. I was very careful. I bought a bubble equipment to put air into the tank and I bought rocks and a couple of places for the fish to hide. I put a thermometer on the side of the tank so I could make sure that the water was a comfortable temperature for the fish. I had a book that told myself and others that the best temperature for the freshwater fish was 69°. The water was 69° when I brought the fish home, however the water was much colder the next time I took the temperature. I could not figure out why the water was cold and it was affecting the fish in a negative way. I stood by the fish tank for a long time and the cooling system came on. As soon as the cooling system started running, my arms got goosebumps and I got a chill. Then I realized that the fish tank was directly under the air vent. Every time the cooling system was running, the cold air was blowing down on the fish tank. The cold air from the air conditioner equipment was easily making the water temperature colder than it should be. When I moved the fish to a bizarre area of the home and anywhere away from the air vents, the temperature was much easier to maintain and the fish looked very cheerful.