oarfish vs king of the herring

oarfish and king of the herring both are nouns.

Word	Noun	Adjective	Verb	Adverb
oarfish	Yes	No	No	No
king of the herring	Yes	No	No	No

As nouns, oarfish and king of the herring are synonyms defined as:

oarfish and king of the herring: thin deep-water tropical fish 20 to 30 feet long having a red dorsal fin

Other synonyms of oarfish include Regalecus glesne, ribbonfish.

oarfish (noun)	king of the herring (noun)
thin deep-water tropical fish 20 to 30 feet long having a red dorsal fin	thin deep-water tropical fish 20 to 30 feet long having a red dorsal fin