I'm assuming you meant cuttlebone not cuttlefish, lol. However you really don't want to give your chinchilla either, too much calcium is a bad thing, it can cause health problems like urinary tract stones. If you are feeding a good quality diet your chin shouldn't need extra calcium. Those mineral "candies" aren't good either, once again if you feed a good diet you don't need supplements, and would do more harm then good. I doubt one "candy" thing a month would do much harm though.