Silverfish are very primitive insects that constitute the Order Thysanura. In Australia, this rather small insect order is represented by only 28 described species. These are agile, fast-running, scale-covered insects that are primitively wingless. About 5 species of silverfish have successfully invaded buildings. These pest species restrict their activities to relatively undisturbed areas (eg; bookcases, storage rooms), where they may damage paper, fabrics and other materials
Silverfish are primitively wingless and have a flattened, slender, scale-covered body. Most have a silvery appearance and, because the body tapers to the rear, they are often said to have a fish-like appearance. Antennae are usually long and slender, and three long appendages from the rear of the abdomen are very conspicuous. The structure of the young is similar to that of an adult.