Silverfish are fairly harmless, but these grayish-blue, serpentine creatures aren't pleasant to have around the house. They feed on books, dead skin cells, and other starchy materials and thrive in dark, wet spaces. Once you've determined you have an infestation, you can get rid of silverfish by trapping them, repelling them, killing them with insecticides, or making your home less hospitable. To prevent silverfish inside infestations, eliminate sources of excessive moisture in places like faulty plumbing and areas of condensation. Silverfish love the humidity. The use of a dehumidifier will reduce moisture content in the air that is essential to silverfish survival. Silverfish can not survive inside buildings in low relative humidity If the relative humidity is above 50% year-round in an air-tight house, silverfish infestations may be difficult to control.