The number one reason a monitor will stop eating is stress.There are a number of thing that could cause the stress,temps to low or high,the humidity is to low,or lack of safety.A monitor kept in a fish tank with no place to hide,and an owner trying to force themselves on them,they are going to stop eating.Lack of safety will cause a monitor to stop eating,in fact it is common for young Water monitors to regurgitate when they become stressed
greg