characin vs characin fish

characin and characin fish both are nouns.

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

As nouns, characin and characin fish are synonyms defined as:

characin and characin fish: any freshwater fish of the family Characinidae

Other synonyms of characin include characid.

characin (noun)	characin fish (noun)
any freshwater fish of the family Characinidae	any freshwater fish of the family Characinidae