|Yellow perch (Perca flavescens)|
Perch have "rough" scales. When looking through a microscope, the scales look like a plate with growth rings and spikes on the top edges. On the top side of the fish, there is a mouth, a pair of nostrils, and two lidless eyes. On the bottom sides are the operculum, which are used to protect the gills. Also perch have a lateral line system, which a set of sense organs that are sensitive to vibrations in the water. They have a pair of pectoral and pelvic fins. On the front end of the fish, there are two dorsal fins. The first one is spiny and the second is soft. There is also an anal fin, which is also considered spiny, and a caudal fin.