dollarfish vs horsehead

dollarfish

noun
  • Peprilus triacanthus, the American butterfish. 

horsehead

noun
  • The head of a horse. 

  • A steel girder supporting the roof of a mine tunnel. 

  • A pump for pumping oil from an oil well. 

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