'''Lepisma saccharina''' (commonly called the 'fishmoth', 'urban silverfish' or just the 'silverfish') is a small, wingless
insect typically measuring from half to one
inch (12–25
mm). Its
common name derives from the animal's silvery blue color, 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 300 million years, originating in the
Palaeozoic Era. Often misidentified as a silverfish is the
house centipede, another house-dwelling arthropod that exhibits rapid, fluid movement.
An eyeless species of silverfish, or a close relative, was discovered in January 2006 in caves in
Sequoia National Park,
California.
Diet
The favourite food of silverfish is any matter that contains starch or
polysaccharides, such as
dextrin in
adhesives. These include
glue, book bindings,
paper,
photos,
sugar,
hair, and
dandruff. Silverfish can also cause damage to books,
tapestries, and
textiles. Silverfish will commonly graze in and around showers, baths, and sinks on the
cellulose present in many shampoos, shaving foams and so on. Apart from these cases, the damage caused by silverfish is negligible and they have no direct effect on human health beyond psychological distress to those who are frightened by their appearance. However, they also have a bite which may cause irritation but has no long term effects. Other substances that may be eaten include
cotton,
linen,
silk and
synthetic fibres, and dead insects or even its own
exuvia (moulted
exoskeleton). During famine, a silverfish may even attack
leatherware and synthetic fabrics. In extreme cases, silverfish may live for a year without eating.
Reproduction
The reproduction of silverfish has only recently been studied. The male lays a
spermatophore, a sperm capsule covered in
gossamer. Having located the spermatophore via a variety of biochemical signals, the female takes up the spermatophore for
fertilization, which will then result in a fertilized egg.
Predation

A silverfish (''Lepisma saccharina'') without its silvery scales, which are only developed after its third moult.
Earwigs,
house centipedes, and in rare cases spiders are known to be
predatory upon silverfish.
Elimination
In buildings, silverfish can only exist in sufficiently
humid, crevice-rich environments. If these two conditions are removed, the silverfish will not be able to survive. Other measures that may be taken to eliminate silverfish, at least temporarily, include the following:
'Non-lethal'
★ By far the most effective way to be rid of silverfish for sure is to keep an area or room tidy, limiting the possible number of breeding grounds they have.
★ Ensuring showers, baths etc. are rinsed clean and free of any residual
toiletries that may attract hungry silverfish.
★ Leaving the bathroom door open after a shower to lessen the humidity
★ The scent of a
sal ammoniac solution should drive away silverfish within 24 hours.
★ To capture silverfish, trap in small glass containers -- silverfish cannot climb up the smooth inside walls.
'Lethal'
★ Silverfish can also be caught by sprinkling
plaster on a wet, white cotton cloth, put it in a corner overnight, near the silverfish's hideout.
★ It is important when filling crevices in which silverfish are living or may potentially live to use a filler material which is either toxic to insects, or does not contain materials which would supply the silverfish with a source of food.
★ A 1:1-ratio dispersion of
borax or
boric acid and sugar is a reliable bait to kill silverfish (relatively non-toxic to non-insects).
★ Adults can be killed by freezing, but it is difficult to kill the eggs.
Notes
#
University of Arkansas: Arthropod Museum Notes 2005
External links
★
Silverfish factsheet at
Virginia Polytechnic Institute and State University
★ http://www.uos.harvard.edu/ehs/pes_silverfish.shtml Harvard University factsheet on silverfish and firebrats
★
Frequently Asked Questions about Silverfish at
Cornell Cooperative Extension, Insect Diagnostics Laboratory
★
Magnified pictures of Silverfish