blenny vs blennioid fish

blenny and blennioid fish both are nouns.

Word	Noun	Adjective	Verb	Adverb
blenny	Yes	No	No	No
blennioid fish	Yes	No	No	No

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

blenny: small usually scaleless fishes with comb-like teeth living about rocky shores; are territorial and live in holes between rocks
blennioid fish: elongated mostly scaleless marine fishes with large pectoral fins and reduced pelvic fins

Other hypernyms of blenny include blennioid.

blenny (noun)	blennioid fish (noun)
small usually scaleless fishes with comb-like teeth living about rocky shores; are territorial and live in holes between rocks	elongated mostly scaleless marine fishes with large pectoral fins and reduced pelvic fins