sheat vs sheatfish

sheat

noun
  • A sheatfish 

sheatfish

noun
  • Other catfish of genus Silurus. 

  • The wels catfish (Silurus glanis), a catfish, the largest freshwater fish in Europe. 

  • Micromeria (syn. Micronema) spp. 

  • Phalacronotus species. 

  • Wallago species, found in the Danube and other Eastern European rivers. 

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