mayfish vs striped killifish

mayfish and striped killifish both are nouns.

Word	Noun	Adjective	Verb	Adverb
mayfish	Yes	No	No	No
striped killifish	Yes	No	No	No

As nouns, mayfish and striped killifish are synonyms defined as:

mayfish and striped killifish: black-barred fish of bays and coastal marshes of the Atlantic and Gulf Coast of the United States

Other synonyms of mayfish include Fundulus majalis, may fish.

mayfish (noun)	striped killifish (noun)
black-barred fish of bays and coastal marshes of the Atlantic and Gulf Coast of the United States	black-barred fish of bays and coastal marshes of the Atlantic and Gulf Coast of the United States