You're busy dusting off a library in your house and as you move a book or two, your eye catches movement. A few more books removed and the culprit seems obvious: silverfish. But on close inspection, the bug isn't a silverfish. What is it? There are number of culprits with multiple legs that like to live in similar areas as silverfish. They range from biological cousins to outright barely similar neighbors. Either way they're all bugs, and they don't intend to do any good to your library. That said, knowing the differences can help with eradication.

Roly-polys are a distant comparison to a silverfish.


Unlike the silverfish which it very much resembles, the firebrat prefers the opposite environments of its silvery cousin. Firebrats can typically be found near sources of heat or higher ambient temperature such as the house heater, the water heater, the oven and even a fire place. Hot water pipes get attention as well. Commonly found in regions that see much warmer winters and hotter summers (i.e. Arizona), firebrats love heat, run around at night in the dark, and run away from any bright light. Unlike silverfish, firebrats have gray spotting. Shape-wise they are very similar to silverfish in body size, length and placement of legs and antennae.

Four-Lined Silverfish

The Ctenolepisma Lineata is also related to the silverfish in terms of bug category. Distinguished by longer legs and a seemingly stronger body structure, this bug version can function in hot and cold climates easily. It prefers warm, but won't die off from the cold. First found in Europe, the four-lined silverfish has migrated with human traffic all over the place and can be found in most populated areas.

The House Centipede

Looking at close-up photos many would wonder how the centipede would get confused with a silverfish, but both are typically seen from a distance as they scurry to hide again. The centipede is noticeably different by its body structure. Typically showing 30 legs, it looks like an elongated hair thistle that moves quickly. The main body core resembles that of a silverfish in length which probably creates the confusion. The benefit to this creature, however, is that it likes to eat other pests such as silverfish, roaches and ants.

Wood Lice

As kids, many people have seen and played with wood lice when exploring outside. Best known as roly-polys, wood lice come in a number of variations. Famous for some versions' ability to roll up tight like an armadillo, the wood lice can be found indoors and outside, typically in damp areas. They are not very similar in shape to silverfish, but they do have the same gray coloring and can be found in similar locations with moisture present.

Carpet Beetle Larvae

While beetles per se have no resemblance to silverfish, their larvae do have similar body structures. Found in the carpet edges where the material tucks under baseboards or behind/underneath furniture, beetle larvae look like small worms with a lot of fuzz on them. They move around with legs in the front of the body and have an elongated abdomen. However, they are nowhere near as fast as silverfish in actual movement.