Name: Lepisma saccharina

Alias: Silverfish are one of the oldest known insects. Silverfish resemble something you would pull out of a pond or sewer, rather than an insect. Adults of the species have a silver-gray body that moves like a fish, hence the name. They lack wings but make up for it in antennae. Their back end has three filaments that look like additional antennae. Silverfish nymphs look similar to the adults, but their bodies are soft and pale. They actively avoid light and prefer to come out only at night. They are known throughout all parts of the world.

Crimes: Silverfish invade homes and prefer areas with warm, damp conditions. They feed on paper, glue, cloth, cardboard and other starchy wood products. They are usually seen as a symptom of bigger problems, such as a moist, wet attic, but heavy infestations can cause significant damage to valuables.

Redeeming Qualities: None known.

Sentence: Silverfish can be easily evicted by reducing the humid conditions that help them thrive. Do not store cardboard boxes directly on concrete. Silverfish can be easily caught by putting masking tape — or any tape with a rough surface — on the outside of a glass jar and filling the inside with dry oatmeal. The silverfish can climb up the tape, but cannot climb out of the glass. If there is a serious problem, a professional exterminator may need to be called to treat with borate.

For more information on dangerous and beneficial bugs, call UI Extension educator Joseph Sagers at 208-745-6685 or email