Insects that have a fish like appearance and movement.  They are bluish-silver in color and are on the small side with long antennae.Most commonly recognize body part is the 3 long bristles at the end of the body.
You maybe finding Silverfish in your home for a couple of reasons:
Excessive Moisture, they love humid, moist areas.Excessive leaf litter to close to the home and entry points.You might ask yourself if it is a bad sign to be finding silverfish in your home?  And the answer is no, they do not cause harm or bite, but are a nuisance to find tons of them everyday in your home.They also can bring in other unwanted pest guest who seek them as a food source.Why do you find silverfish in bathrooms?For the same reason mentioned above, those areas tend to stamp humid.
How to Get Rid of Silverfish?
First you will want to inspect the areas you are finding them inside and outside and see if you can identify excessive moisture.  Leaks, gutter spouts, etc. eliminate those issues.Check to make sure that mulch and leaf litter is not to high and up towards the weep holes or other possible entry points.You can use a Silverfish control product such as Boric Acid in areas of silverfish infestations.  Most dust will stay active for upwards of 6 months if kept dry. You can apply in cracks and crevices, behind baseboards, under carpet seams.An added layer of protection is to apply a residual insecticide to the outside of the home and all entry points.  Harris Home Pest Control Spray is a great option for a ready to use product.
Checkout Our Ultimate Silverfish Control Guide