Key to the Species of Pimephales
1a. Mouth terminal and oblique; caudal spot absent; sides with herringbone lines; lateral line not extending to caudal fin; predorsal scale rows usually 23 to 26.
fathead minnow
Pimephales promelas
1b. Mouth subterminal to terminal; small dark caudal spot present; sides without herringbone lines; lateral line extending to base of caudal fin; predorsal scale rows usually 23 or less.