They don't hurt humans or pets. They'll also tend to hide, given the opportunity.
They do like to eat paper, however. One silverfish isn't a big deal, but if you see them often it's worth looking into deterrents or pest treatment. When there are lots, you'll start to notice holes in notes, books, etc — most particularly (in my experience), loose pieces of paper left undisturbed for a length of time.
Thank you, this looks really good. They have an EOFY deal going for $99.