Silverfish are wingless, flat insects with two long, slender antennae at the front and three long, slender, “bristles,” at the rear of a tapered, carrot-shaped body. They are generally drawn to moisture, and like warm, humid conditions. Their close relative, the firebrat, prefers heat, and will be found in hot areas. They run in a dart movement.
Silverfish have flat, elongated bodies 1/4 to 1/2 inch long and are broad near the head, tapering toward the rear. They have a rather carrot shape to them. They are wingless insects, coveredwith scales and have two long, slender antennae at the head, accompanied by three antennae-like appendages at the rear. One of these points straight back, while the other two curve off to the sides.
The Silverfish adult is about 1/2 inch long with a uniform silvery or pearl-gray color. The four-lined silverfish is about 3/4 inch long and uniform light to dark gray. The young resemble adults except adults, except they are smaller (as one would expect). They will be adults within 3 months.