rock gunnel vs bracketed blenny

rock gunnel and bracketed blenny both are nouns.

Word	Noun	Adjective	Verb	Adverb
rock gunnel	Yes	No	No	No
bracketed blenny	Yes	No	No	No

As nouns, bracketed blenny is a hypernym of rock gunnel; that is, bracketed blenny is a word with a broader meaning than rock gunnel:

rock gunnel: slippery scaleless food fish of the northern Atlantic coastal waters
bracketed blenny: small eellike fishes common in shallow waters of the northern Atlantic

Other hypernyms of rock gunnel include gunnel.

rock gunnel (noun)	bracketed blenny (noun)
slippery scaleless food fish of the northern Atlantic coastal waters	small eellike fishes common in shallow waters of the northern Atlantic