Silverfish and firebrats are very similar in appearance and are therefore best distinguished by their differences in habitat. Silverfish prefer damp, cool places such as basements, laundry rooms, and under sinks.
Silverfish and firebrats have a distinctive fish-like appearance. Their bodies are flat, tapered at both ends, and covered by overlapping scales. They are wingless and small, about 1/2 inch (12.5 mm) in length or less. The antennae are threadlike and very long. They also have three long, thin, tail-like appendages at the end of the abdomen.