Perca is the genus of fish referred to as perch or, sometimes, yellow perch, a group of freshwater fish belonging to the family Percidae. Perch, of which there are three species in different geographical areas, lend their name to a large order of vertebrates: the Perciformes, from the Greek perke meaning perch, and the Latin forma meaning shape.

Perch have "rough" or ctenoid scales. On the anterior side of the head are the maxilla and lower mandible for the mouth, a pair of nostrils, and two lidless eyes. On the posterior sides are the opercula, which are used to protect the gills. Also there is the lateral line system which is sensitive to vibrations in the water. They have a pair of pectoral and pelvic fins. On the anterior 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. Also there is a cloacal opening right behind the anal fin. All perciform fish share the perch's general morphology.'''

The type species for this genus is the European perch.

Perch as a food fish

Perch are a popular panfish and are considered to be very good eating; the commercial catch for them has always been in high demand. This has also led to considerable misuse of the term "perch" in the restaurant business in the United States, such as "ocean perch" (Rosefish) and "rock perch" (a small bass). Many restaurants will strive to correctly advertise the offering as "yellow lake perch", or the slightly more ambiguous "lake perch". "White perch", though similarly popular, is a completely different species of panfish common in New England, and not a member of the order Perciformes.

Angling

They can be caught with a variety of methods, but the two best methods are perhaps float fishing and lure fishing. Spinners work exceptionally well. When Float Fishing, the angler will want to have a disgorger at all times; Perch are notorious for swallowing the hook, and will need aid of a disgorger or forceps for unhooking. In many parts of the world they are also a favorite species among ice fishermen. They will take a variety of baits, including minnows, worms, maggots, bread and softshell crayfish.

Perch grow to around or more, but the most common fish to be caught are around or less, and anything over is considered a prize catch.

Species

Most authorities recognize three species of perch:

• The European perch (Perca fluviatilis) is found in Europe and Asia. It is usually dark green with red fins. The European perch has been successfully introduced in New Zealand and Australia where it is known as the redfin perch or English perch. In Australia they have bred into larger specimens.

• The Balkhash perch (Perca schrenkii) is found in Kazakhstan, (in Lake Balkhash and Lake Alakol), Uzbekistan, and China. It is very similar to the European perch, and grows to a comparable size.