filefish

/ˈfaɪlˌfɪʃ/
noun
  1. A type of tropical marine fish with a rough, file-like skin and a long dorsal fin.
    • Filefish are known for their ability to change color to blend in with their surroundings.
    • We saw a brightly colored filefish while snorkeling in the Caribbean.
    • The filefish swam slowly among the coral reefs.