My entire house has windows everywhere. There is not one spot that doesn't have sunlight touching it. My 10 gallon (no fish yet) is by a window. I am trying not to open up that window. The temperature in the tank was 76-78 degrees and now today it is 74-76 degrees. Is this too cold for guppies? How will the sunlight affect my tank? I also have a 50 gallon my parents are bringing me. The only spot I have for it is by two big windows. Should I just not put up the tank? If I don't open up my windows my house is a dungeon and I hate turning on the lights. Any suggestions?