Pest Exterminator

Silverfish Life Cycle

Life Cycle Stages

The silverfish process from egg to adult usually takes about four months. They are hemimetabolis insects, which means they develop through three stages:

  • Egg
  • Nymph
  • Adult


While silverfish do not reproduce through direct fertilization of the eggs, they do perform a mating dance.

  • The insects touch their antennae together.
  • The female flees.
  • The male and female reunite. They stand side by side while the male vibrates his tail.
  • Males then deposit small packets of sperm into the female ovipositors.


Depending upon climate conditions and species, eggs may take between 19 to 60 days to hatch. Humid conditions are preferable, though silverfish can thrive in almost any environment.

Female silverfish produce one to three eggs per day, or clusters of two to twenty. The pests deposit eggs in cracks around the inside of a home or attic, making them difficult to find. Unlike some other insects, silverfish can produce eggs all year.


When they emerge from the egg, silverfish nymphs are miniature versions of the adults. They go through a number of molts during development, and continue to molt throughout their lives. Some species may undergo more than 50 molts.


Typically, silverfish become adults in about three or four months. In cool climates, it may take up to two years to develop into a mature adult.

Encounters & Concerns

The surrounding environment has a major influence on silverfish development and how long silverfish live. In ideal environments of high temperatures and humidly, these insects can live for about three years.

What do silverfish look like?

Silverfish range from 1/4” to 1” in length. Their bodies consist of a head, abdomen, six legs, two compound eyes, two long antennae, and three appendages that resemble tails. The body of the silverfish is flat and narrow and tapers down from the head in the shape of a carrot. It is covered in shiny, silver-grey scales. Two of the tail-like appendages, called cerci, point to the sides of the body, with the filament (or middle appendage) between them pointing backward. Silverfish do not have wings; they move by using their legs in a wiggling motion that resembles a swimming fish. Silverfish can run quickly on horizontal surfaces but are not as fast when moving vertically. However, they are able to jump up to a foot in the air.

Silverfish grow from egg to nymph to adult. The female lays up to three white, oval-shaped eggs in a crack or crevice. When the eggs hatch — which can vary from a period of three to six weeks depending on temperature — pale nymphs emerge. These nymphs continue to grow into adulthood, molting as they do and developing scales that are dark, shiny, and silver-colored.  The normal lifespan of a silverfish is between two and eight years. Silverfish reproduce at all times of the year, with the female laying about 100 eggs over the course of her lifetime.

What are the risks of a silverfish infestation?

Because they are adept at hiding, silverfish can grow in numbers before being discovered, resulting in a significant infestation. These pests do not bite or directly cause harm to humans or pets, but they are destructive to your home. Silverfish can contaminate foods and eat through fabrics, paper, or other items.

Silverfish eat mold, so their presence may also indicate a mold issue in your home. They are also a preferred food of spiders, centipedes, and other insects, so silverfish in your home may attract these pests.

When are They Active?

You and the silverfish likely have very different schedules, so you may not run into them too frequently unless you wake up in the middle of the night.

A common silverfish encounter usually occurs when someone walks into their bathroom at night and turns on their light to find a silverfish in their bathtub. This is somewhat of a prison for silverfish because they struggle to climb out of bathtubs due to their lack of extra appendages. They are poor climbers, but exceptional runners.

Silverfish are very quick, and can outrun the majority of their predators. Seeing a silverfish run in your home is a very unsettling sight that is sure to send shivers up your spine.

They will often scurry off into dark and secluded places. Silverfish are nocturnal, so they prefer to stay hidden during the brighter hours of the day, and will likely only come out when your lights are off.

The perfect conditions for silverfish are dark environments with temperatures around 70 to 90 degrees Fahrenheit, although they can survive in temperatures above 50 degrees.

Silverfish thrive in moist conditions, so they are often found in parts of your home that may be harboring excess moisture. They are often found in bathrooms, kitchens, laundry rooms, garages, cabinets, or near leaks.

Sign of a Silverfish Infestation

Keep an eye out for feeding marks, although they may be irregular whether they are holes, notches along an edge, or surface etchings. Yellow stains, scales and/or feces (tiny black pepper-like pellets) may also be seen on infested materials.

These pests can typically be found in humid, moist areas of the home including basements, attics and bathrooms. People have noticed silverfish when they come down on ceiling soffits and/or drop from skylights and canister light fixtures in the ceiling, likely entering through shake roofs.

What is the Best Way to Kill Silverfish?

There are numerous ways to kill silverfish, including the use of boric acid and diatomaceous earth. Silverfish can be captured and killed using glasses wrapped in masking tape and filled with sugar water as bait. Another way to get rid of silverfish is to spray a mixture of bleach and water in the areas where they live or points where they access a home. The best way to control silverfish is to make one’s home inhospitable to these insects.

Boric acid is an effective means of silverfish extermination, though it’s a low-grade toxin. Children and pets must be kept away from areas in which boric acid is used. The powder should be sprinkled where silverfish have been noticed. Particular attention should be paid to areas where silverfish like to hide, such as under sinks and in cracks and crevices. More boric acid can be sprinkled every two weeks as needed to kill silverfish.