The escolar a species of fish in the family Gempylidae, is found in deep (200–885 m) tropical and temperate waters around the world. It is also known as snake mackerel, and is sometimes fraudulently marketed as "butterfish" or "white tuna", a controversial practice due to potential health problems related with consumption of the fish. The escolar is dark brown, growing darker with age until it is quite black. It is a fast-swimming fish with a prominent lateral keel and four to six finlets after the anal and second dorsal fins. Escolar can grow to over 2 m in length. Like its relative the oilfish, escolar cannot metabolize the wax esters naturally found in its diet. This gives the escolar an oil content of 14–25% in its flesh.