1a. Snout long, length (A) equal to length of head behind eye (B); circumferential scales usually greater than 30; head and fins of breeding males bluish pink; more than 30 tubercles on head of male, some extending onto snout.
river chub
Nocomis micropogon

1b. Snout short, length (A) less than length of head behind eye (B); circumferential scales usually less than 30; head of breeding males blue, fins bright orange; tubercles on head of male never more than 14, none on snout.
bluehead chub

Click Here