Gambusia affinis vs live-bearer

Gambusia affinis and live-bearer both are nouns.

Word	Noun	Adjective	Verb	Adverb
Gambusia affinis	Yes	No	No	No
live-bearer	Yes	No	No	No

As nouns, live-bearer is a hypernym of Gambusia affinis; that is, live-bearer is a word with a broader meaning than Gambusia affinis:

Gambusia affinis: silvery topminnow with rows of black spots of tropical North America and West Indies; important in mosquito control
live-bearer: small usually brightly-colored viviparous surface-feeding fishes of fresh or brackish warm waters; often used in mosquito control

Other hypernyms of Gambusia affinis include poeciliid, poeciliid fish, topminnow.

Gambusia affinis (noun)	live-bearer (noun)
silvery topminnow with rows of black spots of tropical North America and West Indies; important in mosquito control	small usually brightly-colored viviparous surface-feeding fishes of fresh or brackish warm waters; often used in mosquito control