Silverfish are primitive insects classified in the order Zygentoma. They have carrot-shaped bodies with long, tail-like appendages. Most times, their bodies are covered in metallic-gray scales, leading to the name “silverfish.”


Silverfish are unique arthropods that develop through a process called ametabolous metamorphosis. This means to undergo no metamorphosis or transformation. Many insects go through three or four stages of development that involve significant physical change, such as maturing from larvae to pupae. In the life cycle of a silverfish, an immature silverfish is smaller but nearly identical to an adult silverfish. The main differences in immature silverfish are a lack of scales and functioning genitalia. Ametabolous metamorphosis is considered a primitive development process and is only found in the earliest insects to exist on the planet Earth.

Molting occurs throughout the life cycle of a silverfish. When an insect molts, it sheds its skin to prepare for new growth. Scales do not usually appear on silverfish until the third molt. The number of molts a silverfish undergoes before death has not been agreed upon.


It can take silverfish anywhere from three months to three years to reach full maturity. It is estimated that mature silverfish can live for an additional three years. Development time varies depending on the temperature of the surrounding environment. Ideal temperatures for quick development are typically above 70 degrees Fahrenheit.

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