generally there is some overlap between mice hopper/small adult and rat fuzzy. of course, it all depends on where you're buying. refer to PitOnTheProwl's response above with size chart. with the snake at 50 grams rat fuzzies may be a bit large. finish up the hoppers and by then the snake will likely have gained the weight to move to rat fuzzies or a larger mouse. rat pups definitely too large at his point.