characin fish vs characin

characin fish and characin both are nouns.

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

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

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

Other synonyms of characin fish include characid.

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