I happened to stumble across your post tonight... Do you still have the snake? A word to the wise, aquariums with "weighted tops" have been responsible for more lost pets than one can imagine, and snakes would top the list. Though not totally implausible a Bullsnake would not typically eat a lizard, but rather are inclined to rodents and birds. A baby "Bull" can easily handle a "fuzzy" mouse. That is a mouse with full fur and eyes just opening or nearly so. You can generally buy a live one or a frozen one from any specialty pet store, or frozen from the big chain pet stores. Place it in a cup or even a paper towel tube to simulate a underground passage. If alive it will stimulate predation with it's movement. If frozen thaw thoroughly before placing it in with the snake. Good luck...