fish vs catch

fish and catch both are nouns.

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

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

Other hypernyms of fish include grab.

fish (noun)	catch (noun)
any of various mostly cold-blooded aquatic vertebrates usually having scales and breathing through gills	the act of catching an object with the hands
the flesh of fish used as food	the act of apprehending (especially apprehending a criminal)
	a cooperative game in which a ball is passed back and forth
	a fastener that fastens or locks a door or window
	a restraint that checks the motion of something
	a drawback or difficulty that is not readily evident
	a break or check in the voice (usually a sign of strong emotion)
	anything that is caught (especially if it is worth catching)
	a person regarded as a good matrimonial prospect
	the quantity that was caught

fish (verb)	catch (verb)
catch or try to catch fish or shellfish	come down with
seek indirectly	be struck or affected by
	delay or hold up; prevent from proceeding on schedule or as planned
	detect a blunder or misstep
	discover or come upon accidentally, suddenly, or unexpectedly; catch somebody doing something or in a certain state
	grasp with the mind or develop an understanding of
	become aware of
	be the catcher
	catch up with and possibly overtake
	take hold of so as to seize or restrain or stop the motion of
	succeed in catching or seizing, especially after a chase
	capture as if by hunting, snaring, or trapping
	to hook or entangle
	attract and fix
	cause to become accidentally or suddenly caught, ensnared, or entangled
	spread or be communicated
	take in and retain
	reach with a blow or hit in a particular spot
	apprehend and reproduce accurately
	attract; cause to be enamored
	reach in time
	hear, usually without the knowledge of the speakers
	perceive with the senses quickly, suddenly, or momentarily
	see or watch
	suffer from the receipt of
	perceive by hearing
	get or regain something necessary, usually quickly or briefly
	check oneself during an action
	start burning