frostfish

[frawst-fish, frost-]
noun, plural (especially collectively) frost·fish, (especially referring to two or more kinds or species) frost·fish·es.
  1. either of two North American fishes, the tomcod of the Atlantic Ocean or the round whitefish, that appear when frost sets in.
  2. cutlassfish.

Origin of frostfish

An Americanism dating back to 1625–35; frost + fish
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018