Mail-Cheeked Fishes (Scorpaeniformes) are a group of fishes with both body and head appearing to be spiny or covered by bony plates. The name is derived from the Greek skopaina, a term used to refer to the diminutive of scorpion in allusion to the presence of numerous spines.
The pectoral fins of Mail-Cheeked Fishes are normally rounded, large and with a membrane, often incised, between the spokes. In most species, the caudal fin is rounded, although there are species with truncated caudal fins and rarely forked.
Predominantly carnivorous, they feed mostly on Crustaceans and fish. The vast majority of Mail-Cheeked Fishes inhabit the shallow water seabed, although deep water species also occur. The average size among the species is 30 cm long, with very varied sizes, from the scant 2 cm of the aploactinids (Aploactinidae), to over 150 cm as is the case of Ophiodon elongatus. There are 41 families and 398 genera described that include a total of 2,092 species of Mail-Cheeked Fishes.