Fishes of the order Scorpaeniformes, called the mail-cheeked fishes, are distinguished by a unique character, the suborbital stay. The stay is an extension of the hypertrophied third infraorbital bone, which crosses the cheek obliquely and usually is firmly attached to the preoperculum. The head is usually spiny, and the body may be spiny or have bony plates, or both, or be smooth and appear naked. Almost all scorpaenids have prominent pectoral fins, either broad and fanlike or winglike, with the lower rays deeply incised. The order consists of about 1271 species and 266 genera in 25 families.

• Order Scorpaeniformes
•  Suborder Dactylopteroidei (flying gurnards)
•      Scorpaenoidei (scorpionfishes)
•      Platycephaloidei (searobins and flatheads)
•      Anoplopomatoidei (sablefishes)
•      Hexagrammoidei (greenlings)
•      Normanichthyiodei (no common name)
•      Cottoidei
•       Superfamily Cottoidea (sculpins and poachers)
•       Cyclopteroidea (lumpfishes and snailfishes)