my nile monitor is acting strange. I've had him for a year now and he wont eat and is acting unusually timid. He is 18 inches long, 1 year old and is in a 125 gallon enclose. His substrate is coconut bark. I feed him mostly ground beef, shrimp, and large mealworms and that's what I have always fed him. I handle him daily. but in the past week he is been acting timid and hasn't eaten in the past two days. Please someone respond quickly.