Key to the Species of Cyprinella

1a. Pigmentation on scales above and below lateral line in diamond-shaped pattern (if pattern weakly developed laterally, then pattern typically present ventrolaterally); distinct dark caudal spot present or absent, no barbel in corner of mouth; mouth inferior or terminal; lateral line scale rows less than 50; dorsal fin with or without dark spot posteriorly.

Click Here

1b. Pigmentation on scales above and below lateral line generally uniformly distributed and not in diamond-shaped pattern; distinct caudal spot present; mouth inferior and usually with small barbel in corners; lateral line scales greater than 50; dorsal fin usually with dark spot posteriorly.
spotfin chub

Cyprinella monacha