Silverfish (Lepisma saccharina)


Class: Insecta
Order: Thysanura
Family:    Lepismatidae
Size:    Length: 0.33 to 0.75 inch (8.3 to 19 mm)
Weight: Unknown
Diet: Paper, glue, cereal, flour and sugar
Distribution: Worldwide in temperate climates
Young:  25 to 50 eggs
Animal Predators:  Unknown
IUCN Status: No special status
Terms: Young: Nymph
Lifespan: 2 to 3 years



·         Silverfish can live for several months without food.

·         These tiny, fragile insects have been around more than 400 million years.

·         Silverfish are closely related to the firebrat, an insect with similar looks and similar habits.

·         They are sometimes called “sugar mites” or “bristletails.”

·         Silverfish have the ability to jump, and their eyes glow at night if a light is shone at them.

·         Silverfish belong to the order Thysanura, which is derived from the Greek “thysano” meaning fringed and “ura” meaning tail.



Silverfish have a silver, flattened, carrot-shaped body covered in scales, giving them a resemblance to fish, which is likely how they got their name. They have no wings, but are able to move extremely quickly on their legs. They shed their skin often, leaving behind an empty shell. They have small black eyes, two antennae and three tail filaments. Each of these tail filaments is almost as long as the silverfish’s body. 



Silverfish can be found worldwide, especially in areas where the air is warm and humidity ranges from 75 to 95 F (23 to 35 C) such as tropical forests and grasslands. The natural habitat of a silverfish is outdoors under rocks, logs, tree bark and/or leaves. They are usually carried into a house in a log crevice with firewood, or from other houses in old books, papers or furniture. They prefer moist, humid areas, so are often found in the bathroom. Because they are nocturnal and hide during the day, silverfish are rarely seen.


Feeding Habits

Silverfish feed on all kinds of things found in a house, including paper, glue, cereal, flour and sugar. Though they may bite tiny holes in textiles of vegetable origin such as cotton or linen, they do not actually ingest the fabric. 



There is no set mating season for silverfish. A male places sperm on the ground, then looks for a female and brings her to the sperm. She picks it up to fertilize her eggs. A female lays approximately 100 eggs in her lifetime. She usually lays one to three eggs at a time and leaves them in crevices or scattered in soil. The tiny white eggs hatch anytime from two weeks to two months later. The young silverfish, called nymphs, look much like adult silverfish, but are smaller and white. They do not attain the silver colour of adults until they are four to six weeks old. The nymphs go through six or seven moults before reaching sexual maturity. Silverfish populations grow slowly—if many are found in a house, it has taken years to reach that level. If only a few are spotted at any given time, the infestation is not serious and the best method of getting them out of the house is to gently carry them outdoors. They do not re-enter unless carried inside again. 



Although they are considered a nuisance when they get into homes, silverfish are generally harmless creatures and have no effect on human health. When they are surprised by a light suddenly being turned on at night, they quickly scurry away.



Silverfish are not of conservation concern.