Silverfish are teardrop shaped insects that are typically silver or gray in color. They have two long antennae and three long bristles that extend from their abdomen. Adult silverfish grow to be about ¾ of an inch long. The most common species of silverfish in the U.S. is called the common North American silverfish. Because of their eating habits, silverfish in your home can contaminate food and damage items like books, clothing, carpets, furniture, pictures, and wallpaper.