turning down food a day or two aftr feeding is odd behavior. Alex seems to have hit on the biggest issues already. Ill just add to stay clear of mealworms completely, their exoskeleton is problematic for fbts to digest and their size can also present problems as fbts only grow to be 1 or 2 inches. Small pebbles should be avoided to use in the tank because they could be swallowed. Continue to monitor your toads behavior