i clip my adults nails with regular nail clippers. if you look at the nail you can see a part that changes color, if you clip any of that part he will bleed, however if you stay past that part he wont bleed. i have granite in my tank and he still gets really long nails and i have to clip them. he will be fine after they are clipped. as i said i do it to mine(about every 6 mo or so). good luck