Photo diagnosis?

[carlcmc]

Examine the snout of this sucker. The fish were spawning and rubbing all over each other, flipping here and there in the water. Is this related?

[Roughfisher]

The bumps on the snout (and fins, and body) of the sucker are called TUBERCULES. These are hard, whitish bumps that form when the fish are spawning. In most species of suckers, only the males develop tubercules. The tubercules supposedly help them stick to the female better while spawning. Once the male suckers are finished spawning, the tubercules disappear.

Many species of minnows also develop tubercules while spawning, especially chubs.