live-bearer vs platy

live-bearer and platy both are nouns.

Word	Noun	Adjective	Verb	Adverb
live-bearer	Yes	No	No	No
platy	Yes	No	No	No

As nouns, platy is a hyponym of live-bearer; that is, platy is a word with a more specific, narrower meaning than live-bearer:

live-bearer: small usually brightly-colored viviparous surface-feeding fishes of fresh or brackish warm waters; often used in mosquito control
platy: small stocky Mexican fish; popular aquarium fish

Other hyponyms of live-bearer include Gambusia affinis, mosquitofish, Platypoecilus maculatus, mollie, molly.

live-bearer (noun)	platy (noun)
small usually brightly-colored viviparous surface-feeding fishes of fresh or brackish warm waters; often used in mosquito control	small stocky Mexican fish; popular aquarium fish