oarfish vs soft-finned fish

oarfish and soft-finned fish both are nouns.

Word	Noun	Adjective	Verb	Adverb
oarfish	Yes	No	No	No
soft-finned fish	Yes	No	No	No

As nouns, soft-finned fish is a hypernym of oarfish; that is, soft-finned fish is a word with a broader meaning than oarfish:

oarfish: thin deep-water tropical fish 20 to 30 feet long having a red dorsal fin
soft-finned fish: any fish of the superorder Malacopterygii

Other hypernyms of oarfish include malacopterygian.

oarfish (noun)	soft-finned fish (noun)
thin deep-water tropical fish 20 to 30 feet long having a red dorsal fin	any fish of the superorder Malacopterygii