Lepisma saccharina (commonly called the fishmoth, urban silverfish or just the silverfish) is a small, wingless insect typically measuring from a half to one inch (12–25 mm). Its common name derives from the animal's silvery blue colour, combined with the fish-like appearance of its movements, while the scientific name indicates the silverfish's diet of carbohydrates such as sugar or starches. It belongs to the basal insect order Thysanura, and the species is estimated to have existed for over 300 million years, originating in the Paleozoic Era. Often misidentified as a silverfish is the house centipede, another house-dwelling arthropod that exhibits rapid, fluid movement.
The reproduction of silverfish is preceded by a "love dance", involving three phases, which may last over half an hour. In the first phase, the male and female stand face to face, their trembling antennae touching, then repeatedly back off and return to this position. In the second phase the male runs away and the female chases him. In the third phase the male and female stand side by side and head-to-tail, with the male vibrating his tail against the female. Finally the male lays a spermatophore, a sperm capsule covered in gossamer, which the female takes into her body via her ovipositor to fertilize the eggs she will lay later on.
Juvenile silverfish are white in color.
Under laboratory conditions, silverfish may go through between 17 and 66 molts, much more than usual for an insect. Silverfish are one of the rare insects that continues to molt after mating.