eelpout vs blennioid fish

eelpout and blennioid fish both are nouns.

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

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

eelpout: marine eellike mostly bottom-dwelling fishes of northern seas
blennioid fish: elongated mostly scaleless marine fishes with large pectoral fins and reduced pelvic fins

Other hypernyms of eelpout include blennioid.

eelpout (noun)	blennioid fish (noun)
marine eellike mostly bottom-dwelling fishes of northern seas	elongated mostly scaleless marine fishes with large pectoral fins and reduced pelvic fins
elongate freshwater cod of northern Europe and Asia and North America having barbels around its mouth