smallmouth bass vs smallmouthed bass

smallmouth bass and smallmouthed bass both are nouns.

Word	Noun	Adjective	Verb	Adverb
smallmouth bass	Yes	No	No	No
smallmouthed bass	Yes	No	No	No

As nouns, smallmouth bass and smallmouthed bass are synonyms defined as:

smallmouth bass and smallmouthed bass: a variety of black bass; the angle of the jaw falls below the eye

Other synonyms of smallmouth bass include Micropterus dolomieu, smallmouth, smallmouth black bass, smallmouthed black bass.

smallmouth bass (noun)	smallmouthed bass (noun)
a variety of black bass; the angle of the jaw falls below the eye	a variety of black bass; the angle of the jaw falls below the eye
flesh of smallmouth bass