English
frostfish
From frost + fish.
Proto-Indo-European *prews- ‘to freeze’
…
Proto-Germanic *frustaz
Proto-West Germanic *frost
Old English frost
Middle English frost ‘Cold or freezing weather’
English frost
Proto-Indo-European *piskós
Proto-Germanic *fiskaz
Proto-West Germanic *fisk
Old English fisċ
Middle English fisch ‘an animal that inhabits the water or the meat…’
English fish
The story
In the case of the tomcod, so called because it is abundant on the New England coast in autumn at about when frost comes.
Today it means
noun Microgadus proximus
Language periods are conventional ranges, not dates for this word.
Etymograph / frostfish