Q: My hamster is 1-year-old and his nails are going black. I am really worried about him. Do you know what is wrong with him?
A: It is difficult to say without seeing your hamster if this is a cause for concern. If you are using a substrate that is colored or has colored ink (such as newspaper), this can discolor the nails of your hamster.
If you are certain there is not a color dye that is causing the problem, then I would worry about disease. Nail bed infections can cause what you are seeing. This can include both bacterial infections and fungal infections. Since both of these types of infections can be treated, visit a veterinarian who treats hamsters.
If this is an infection and it is left untreated, the infection can spread from the nails to the rest of the body.