The term Perch commonly refers to several species, but most notably the Yellow Perch (Perca flavescens). These fish are small to medium in size, usually reaching up to 12 inches in leng... The term Perch commonly refers to several species, but most notably the Yellow Perch (Perca flavescens). These fish are small to medium in size, usually reaching up to 12 inches in length. They have a yellowish body with dark vertical stripes and are found in lakes, ponds, and rivers. Perch are schooling fish that feed on small invertebrates and fish. They are popular among anglers for their taste and are often used in recreational fishing.Click here to read more about Perch.