shad vs clupeid fish

shad and clupeid fish both are nouns.

Word	Noun	Adjective	Verb	Adverb
shad	Yes	No	No	No
clupeid fish	Yes	No	No	No

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

shad: herring-like food fishes that migrate from the sea to fresh water to spawn
clupeid fish: any of numerous soft-finned schooling food fishes of shallow waters of northern seas

Other hypernyms of shad include food fish, clupeid.

shad (noun)	clupeid fish (noun)
herring-like food fishes that migrate from the sea to fresh water to spawn	any of numerous soft-finned schooling food fishes of shallow waters of northern seas
bony flesh of herring-like fish usually caught during their migration to fresh water for spawning; especially of Atlantic coast