scorpion fish vs scorpionfish

scorpion fish

scorpionfish

noun
  • Any of the family Scorpaenidae of mostly marine fish, including many of the world's most venomous species, the "sting" taking the form of sharp spines coated with venomous mucus. 

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