characin vs tetra

characin and tetra both are nouns.

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

As nouns, tetra is a hyponym of characin; that is, tetra is a word with a more specific, narrower meaning than characin:

Other hyponyms of characin include cardinal tetra, Paracheirodon axelrodi, caribe, pirana, piranha.

characin (noun)	tetra (noun)
any freshwater fish of the family Characinidae	brightly colored tropical freshwater fishes