headfish vs sunfish

headfish

noun
  • The sunfish (of family Molidae). 

sunfish

noun
  • Any of various large marine fishes of the family Molidae that have an oval compressed body. 

  • Any of various small freshwater fishes of the family Centrarchidae, often with iridescent colours and having a laterally compressed body. 

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