silverfish, common name for primitive, wingless insects of the family Lepismatidae. The silverfish, which has two long antennae and three long tail bristles, is named for its covering of tiny, silvery scales. It develops directly in six or more molts into an adult about 1/2 in. (1.27 cm) long. It has chewing mouthparts set in a head cavity and eats starch from book bindings, wallpaper, and clothing. The silverfish is common indoors in cool, damp places such as basements. The firebrat, in the same taxonomic family, is found in warm places, e.g., near steampipes and boilers. Silverfish are classified in the phylum Arthropoda, class Insecta, order Thysanura, family Lepismatidae.