What is the meaning of the word "jackknife-fish"?

Definitions:

  1. A marine fish species known for its elongated, knife-like dorsal fin and typically found in the Atlantic Ocean, particularly around coral reefs, often recognized for its striking black and white coloration. copy to clipboard NOUN
    • The jackknife-fish is a popular species among marine aquarium enthusiasts due to its unique appearance. copy to clipboard
  2. A type of marine fish known for its distinctive appearance, particularly its long, pointed dorsal fin that resembles the blade of a jackknife. copy to clipboard NOUN
    • Maintaining a jackknife-fish in an aquarium requires careful attention to water quality and tank conditions. copy to clipboard
  3. Black-and-white drumfish with an erect, elongated dorsal fin. copy to clipboard NOUN
    • Divers in the Caribbean frequently spot jackknife-fish near coral formations, where they hunt for small prey. copy to clipboard

Synonyms: