It is easiest to keep them in an escape-free bowl that you can get at any pet store. My leo wouldn't even look at them the first month I had her. I had to basically give her a trail of mealworms to the dish and then one hanging on the side of the dish for her to finally look in there. Even still she only eats what is moving at the time she looks. If yours is the same and only eats the moving ones, you can either put gutload in the dish because they wiggle more when they eat, or move them to a warm area of the tank, if they aren't already.