We are trying to train a 5 month old panther to eat from a feeder cup so we can prepare him for a larger cage but he refuses to eat from it. It is about 2 inches deep and is white. We have placed it in different areas of the tank but he still won't use it. We have tried not putting in any loose ones for a few days but he still refuses to eat from it. He has stared at it but won't eat from it. We have tried different amounts in the cup and nothing. We have been trying for a month now. He is one stubborn little guy. Any suggestions on how to get him to use it.