Male creek chubs are nest builders. They build nests by moving around gravel and pebbles, females spawn over the nests (eggs sink) and as the male guards the nest he also expands it for (hopefully) future spawnings with other females. A successful male will have a nest that looks like a gravel ridge in the stream. As to why you've only seen females, I'm honestly not sure...
--Bruce Stallsmith
deep in 'bama somewhere