MHD and Sleeping

Question
I purchased a Mountain Horned Dragon yesterday (June 19 2008) and when he went to sleep he chose to sleep beside his fountain and i noticed he had his tail in the water. I turned of the lights because i was instructed to do so. When i woke up to check on him, he was still, VERY frigid, and his sides weren't moving showing breathing, so i turned on the heat lamp and put him on his basking rock, he started to warm up and breathe from what it looks like and he was eating in about 20 minutes. My question is should i have left the light on at night, and put him away form the fountain? and if i did anything wrong?
Thanks for your time. :)

Answer
Hi Corey, The metabolism of reptiles will slow in relation to the ambient temperature. Their breathing rate and even their ability to move can be affected, that is quite normal. The light should be off at night to mimic the day/ night light period and night time temperature drop that he would normally experience in the wild. You didn't do anything wrong. In fact the husbandry mistake that people usually make with MHD is keeping them too warm and too dry. As their name suggests they are high elevation dwellers, living in the somewhat cooler and very humid cloud forests. Your fountain should help keep the humidity up along with regular misting. You will need only a low wattage basking light to bring the temperature up to the 75 - 80F range in one end of the tank. If he has settled in enough to start feeding for you already then it sounds like he is doing well.