Silverfish

All members of the order Thysanura have a teardrop/carrot/fishshaped body and get their common name of bristletail because of their three long, bristle-like or tail-like appendages on the posterior/rear end of their body. Silverfish is a common name for species of the group whose bodies are covered with silvery scales. Silverfish are found throughout the United States and the world.

Recognition

Adult body length, not including tails, is about 1/2-3/4 inch. Wingless with flattened body. Shape teardrop/carrot/fishlike, tapering from head to rear and generally covered with scales. Color silvery to gunmetal, one species with dark lines running length of body. Antennae long, threadlike. Posterior end of abdomen with three long, bristle-like appendages; tarsi three or four segmented; some abdominal segments with a pair of styli; abdominal sternites lack median setal combs, or if present, last abdominal tergite longer than wide; abdominal tergites with outer dorsal setal combs, or if lacking, last abdominal tergite longer than wide.

Immatures are similar to adults in appearance, except for size. Scales appear with third or fourth molt.

Habits

All these silverfish species hide during the day and prefer to hide or rest in tight cracks or crevices. They can be found almost anywhere in a house. Silverfish infest commercial structures such as offices, stores, and libraries. They tend to roam considerable distances while searching for food, but once they find a satisfactory food source, they remain close to it. Within structures, they can breed in a variety of areas, including wall voids, in or under the subflooring, attics, etc. Silverfish can survive for weeks without food or water.