The Perciformes are an order of the bony fish and occur worldwide in all types of waters. They contain about 10000 species, of which 20% are freshwater fish. In addition, about 40% of all fish belong to the order of Perciformes. More recently, there have been new findings on the taxonomy of the perch-like fish.
Perciformes is composed of the Greek word “perke” (perch) and the Latin “forma” (form). Accordingly, it is literally perch form or perch like. Sometimes they are also referred to as Serraniformes or perchfish.
The Perciformes are characterized by a spindle-shaped body structure and two back fins, which are clearly separated from each other or pass into each other, of which the anterior part is hard and the posterior is soft. The pelvic fins are positioned far forward under the chin or under the belly.
The body of most species is covered by ctenoid scales and the gill cover is often stacked with thorns.
A bone of the shoulder girdle, the Mesocoracoid, is missing and their swim bladder is closed.
There are between 500 and 600 different Species of Cichlidae in Lake Victoria, even though the lake was dried up 15,000 years ago. In comparison, there are only about 200 different freshwater fish in European lakes. Many of the species can only survive because they are highly specialized.
Some 2200 species of Perciformes are born in the sea, but spend most of their adult life in fresh water.
Most species are predators and prefer to stay close to the coast.