wrasse vs blackfish

wrasse and blackfish both are nouns.

Word	Noun	Adjective	Verb	Adverb
wrasse	Yes	No	No	No
blackfish	Yes	No	No	No

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

wrasse: chiefly tropical marine fishes with fleshy lips and powerful teeth; usually brightly colored
blackfish: large dark-colored food fish of the Atlantic coast of North America

wrasse (noun)	blackfish (noun)
chiefly tropical marine fishes with fleshy lips and powerful teeth; usually brightly colored	female salmon that has recently spawned
	small dark-colored whale of the Atlantic coast of the United States; the largest male acts as pilot or leader for the school
	large dark-colored food fish of the Atlantic coast of North America