herring vs bloater

herring and bloater both are nouns.

Word	Noun	Adjective	Verb	Adverb
herring	Yes	No	No	No
bloater	Yes	No	No	No

As nouns, bloater is a hyponym of herring; that is, bloater is a word with a more specific, narrower meaning than herring:

herring: valuable flesh of fatty fish from shallow waters of northern Atlantic or Pacific; usually salted or pickled
bloater: large fatty herring lightly salted and briefly smoked

herring (noun)	bloater (noun)
commercially important food fish of northern waters of both Atlantic and Pacific	large fatty herring lightly salted and briefly smoked
valuable flesh of fatty fish from shallow waters of northern Atlantic or Pacific; usually salted or pickled