coalfish vs stromateid

coalfish

noun
  • any of several blackish fish, especially Pollachius virens, a pollack, and Anoplopoma fimbria, sablefish. 

stromateid

noun
  • Any fish in the family Stromateidae, the butterfishes. 

How often have the words coalfish and stromateid occurred in a corpus of books? (source: Google Ngram Viewer )