fillet gloves
Edge-proof (but not point-proof) gloves made out of some tough yet flexible material, such as kevlar, to protect your hands while filleting fish.
Unlike mice and rats, hamsters and gerbils usually bite when they are first handled, and then they stay in their cage for the rest of their life. If you buy your kid a hamster or a gerbil that has not been handled a lot, then buy some fillet gloves and handle it yourself for about a week until it gets really tame.