piranha vs characin fish

piranha and characin fish both are nouns.

Word	Noun	Adjective	Verb	Adverb
piranha	Yes	No	No	No
characin fish	Yes	No	No	No

As nouns, characin fish is a hypernym of piranha; that is, characin fish is a word with a broader meaning than piranha:

piranha: small voraciously carnivorous freshwater fishes of South America that attack and destroy living animals
characin fish: any freshwater fish of the family Characinidae

Other hypernyms of piranha include characid, characin.

piranha (noun)	characin fish (noun)
small voraciously carnivorous freshwater fishes of South America that attack and destroy living animals	any freshwater fish of the family Characinidae
someone who attacks in search of booty