lookdown fish vs horsefish

lookdown fish and horsefish both are nouns.

Word	Noun	Adjective	Verb	Adverb
lookdown fish	Yes	No	No	No
horsefish	Yes	No	No	No

As nouns, horsefish is a hypernym of lookdown fish; that is, horsefish is a word with a broader meaning than lookdown fish:

lookdown fish: similar to moonfish but with eyes high on the truncated forehead
horsefish: any of several silvery marine fishes with very flat bodies

Other hypernyms of lookdown fish include Atlantic moonfish, dollarfish, horse-head, horsehead, moonfish, Selene setapinnis.

lookdown fish (noun)	horsefish (noun)
similar to moonfish but with eyes high on the truncated forehead	any of several silvery marine fishes with very flat bodies