bullhead vs sculpin

bullhead and sculpin both are nouns.

Word	Noun	Adjective	Verb	Adverb
bullhead	Yes	No	No	No
sculpin	Yes	No	No	No

As nouns, sculpin is a hypernym of bullhead; that is, sculpin is a word with a broader meaning than bullhead:

bullhead: freshwater sculpin with a large flattened bony-plated head with hornlike spines
sculpin: any of numerous spiny large-headed usually scaleless scorpaenoid fishes with broad mouths

bullhead (noun)	sculpin (noun)
freshwater sculpin with a large flattened bony-plated head with hornlike spines	any of numerous spiny large-headed usually scaleless scorpaenoid fishes with broad mouths
any of several common freshwater catfishes of the United States