I cover mine when they're ready to sleep, don't keep it in their tanks during the day, because they will get under them if they don't want to bask. You can also wrap them up, if they'll allow it, we call it burritos and they'll stay that way all night! I have a small place, a 1 bedroom and 5 dragons, so I have to use the living room and bedroom, which is why they have fleece blankets that they're covered with so they sleep in the dark, which makes for better sleep for them. I had a friend make them, they're wonderful! And the dragons love them, so soft and warm!