Have you tried forcepts? Hold the cricket up to his/her face and rub it on his/her mouth. Your frog is a very small baby and needs food items that are no larger than the distance between the frogs eyes. When you drop them in make sure to drop them in front of the frog. Try only to mist when the humidity is below ideal range. More than this may be stressing your frog. Try the forcepts/tweezer idea. Hold the back of the cricket so there is plenty for the frog to bite on without grabbing the forcepts/tweezers. Try buying and infrared light for night time use as well. Sometimes I think the blue night lights do actually impare their eyesight.