Scorpaeniformes, also called mail fish, any of a group of bony fish characterized by a plate of bone running through each cheek. The Scorpionfish are widespread in the world's oceans. They are believed to have originated in warm marine waters but have invaded the temperate and even Arctic and Antarctic seas, as well as the fresh waters of the Northern Hemisphere. They are a very successful biological group, occurring in the sea from the middle of the littoral zone (coast) to depths of at least 4,000 meters (about 13,100 feet). Scorpions inhabit some deep freshwater lakes but are more abundant in cold streams and rivers.
Scorpaeniformes are often divided into seven suborders, only three of which have more than one family: the Scorpaeniformes (12 families), the Platycephaloidei (five families), and the Cottoides (11 families). The best known groups are the scorpion fish and the rockfish (family Scorpaenidae); Marine robins, or gurnards (Triglidae); Flat head (Platycephalus); And shacks (Cottidae). Flying gurnards (Dactylopteridae) are considered by some species to belong to this order, while others place them in the Dactylopteriformes order. Since the Scorpaeniformes are closely related to the Perciformes, some authorities classify the group as a suborder of the Perciformes.
Many members are locally important commercial fish. North Atlantic and Pacific crabs of the genus Sebastes are of considerable value to the fishing industries of Europe, Russia, and North America; Flatheads are exploited in a wide area of the Indo-Pacific region; and greenlings (Hexagrammidae) are of commercial importance in the northwest Pacific. In general, the fishing value of the group as a whole has a potential greater than that shown by actual actual use by humans.
Scorpionfish are not large fish. Some of the deep-sea species, such as gallines, grow to a length of 0.9 meters (about 3 feet), but most reach a maximum length of about 30 centimeters (12 inches). Externally, Scorpionfish vary greatly; Most are like perciformes in general appearance, that is, they are typical, scaled, spiny-ray fish, but the lupus (Cyclopteridae) among them are obese and often jelly-like, usually without scales, and lacking fine spines. However, the body armor is usually well developed and most Scorpions are well equipped with spines.
