shark vs fish

shark and fish both are nouns.

Word	Noun	Adjective	Verb	Adverb
shark	Yes	No	Yes	No
fish	Yes	No	Yes	No

As verbs, fish is a hypernym of shark; that is, fish is a word with a broader meaning than shark:

shark (noun)	fish (noun)
any of numerous elongate mostly marine carnivorous fishes with heterocercal caudal fins and tough skin covered with small toothlike scales	any of various mostly cold-blooded aquatic vertebrates usually having scales and breathing through gills
a person who is unusually skilled in certain ways	the flesh of fish used as food
a person who is ruthless and greedy and dishonest

shark (verb)	fish (verb)
hunt shark	catch or try to catch fish or shellfish
play the shark; act with trickery	seek indirectly