How Big Can They Get?

Silverfish are small, wingless insects with scales that look like fish. They are nocturnal, meaning they are active at night and hide during the day.

Adult silverfish grow to about half an inch long, and have a gray or silvery metallic appearance. Their antennae are threadlike, and their mouths are soft.

Silverfish are moisture-seeking pests, and prefer to live in dark, humid areas. They are omnivorous, and eat starches and carbohydrates in paper, cardboard, and other materials. They also eat protein and organic dyes.

Silverfish are not known to spread disease or bite humans, although some people have experienced allergic reactions to them. The bites are a light scratch that does not cause much damage.

Silverfish molt several times during their lifetime. When they molt, they become smaller. It takes them three months or more to go through a full transformation.

Female silverfish lay a clutch of seven to 12 eggs at a time. Typically, they are laid in tiny cracks and crevices. These eggs are hard to see with the naked eye, but a magnifying glass can help.

Silverfish eggs hatch after about 20 days at 32 deg. C, but can take up to 40 days at 22 deg. A silverfish nymph is only about one-third of an inch long.

A silverfish molts about 50 times during its life. During the molt, the female picks up the sperm package from the male. She then deposits it close to the silk structure. This fertilizes the eggs.