It has a lid, I was just afraid to put it on because it was very hot, and I didnt want him to overheat or something. I made a a new lid out of an old peice of a guinea pig enclosure, its pretty heavy and works well, letting air in, etc. The enclosure is 3ftlong, and 14 inches wide. Its only temporary though. He will soon be moved to an indoor pond that is 210 gallons that will house him, and one other turtle.