2a. (From 1b.) Dark crescent-shaped mark on snout between nostril and upper lip; no dusky stripe along side; peritoneum with little or no pigmentation, appearing silvery or white; pigment on lateral scales not distributed in diamond-shaped pattern; dark caudal spot distinct.
bullhead minnow
Pimephales vigilax

2b. (From 1b.) No dark crescent-shaped mark on snout between nostril and upper lip; dusky stripe present along side; peritoneum heavily pigmented, appearing black; pigment on lateral scales distributed in diamond- shaped pattern (crosshatched); dark caudal spot connected to lateral stripe and not distinct.
bluntnose minnow
Pimephales notatus