frost fish
noun
1 North American the tomcod, Microgadus tomcod (family Gadidae), which becomes abundant on the east coast of North America in the late autumn.
2 NZ the scabbardfish, Lepidopus caudatus (family Trichiuridae), of temperate seas worldwide, known for sometimes becoming stranded ashore in the winter months.
Origin
Mid 17th century; earliest use found in William Wood (fl. 1629–1635), writer on America.