One of my longtail lizards starting exhibiting strange behavior a few days ago. I see him in his tank thrashing, whipping his tail, and often lying on his side or upside down. He shows no other obvious signs of disease, and the other two lizards in his tank (a longtail and a green anole) are behaving normally. I've uploaded a photo of him on his back (and yes, he is still alive). Any idea what this could be?