You will typically see silverfish crawling on walls in or near the bathroom or kitchen. They are about an inch long. In order for a silverfish to reproduce, their environment must be over 98 degrees. Silverfish usually reproduce in the attic, then they find an upstairs bathroom with plenty of water. when you find silverfish downstairs, that means they are having to compete with other pests to find a place to live. They eat glue behind wallpaper, paper in bindings, carpet, etc.