Stones are occasionally picked up in the mouth and carried upstream. Depressions are up to a foot in diameter. Males fight continually during the operation, even to the point of blinding one another with their breeding tubercles. The creek chub chooses a spot over a sand and gravel bottom just above a riffle, then digs by forcing his head into the bottom and shaking vigorously. Sand and pebbles are placed upstream in a long ridge parallel to the course of the stream and varying from 1 to 18 feet in length.
Subsequent digging covers the eggs.
The bluntnose minnow and fathead minnow fasten their eggs under stones in depressions they have dug. Just before spawning season, males of many minnow species take on bright colors, including red and orange. In species that are nest builders, the males are usually larger and more brightly colored. The tubercles help to hold the female during spawning and serve as protection. After the spawning season the tubercles fall off and the males lose most or all of their bright colors.