fishtail vs slow down

fishtail and slow down both are verbs.

Word	Noun	Adjective	Verb	Adverb
fishtail	No	No	Yes	No
slow down	No	No	Yes	No

As verbs, slow down is a hypernym of fishtail; that is, slow down is a word with a broader meaning than fishtail:

Other hypernyms of fishtail include decelerate.

fishtail (verb)	slow down (verb)
slow down by moving the tail sideways	become less tense, rest, or take one's ease
	lose velocity; move more slowly
	become slow or slower
	reduce the speed of
	cause to proceed more slowly