Fathead minnows ( Pimephales promelas Rafinesque, 1820) occur commonly in small lakes across the prairie region of North America. Males establish nests, court females, and tend the eggs. In our study population in Minnesota, males choose between two distinct nest substrates that differ in exposure to abiotic conditions affecting egg development: the underside of pond-lily (genus Nuphar Sm.) pads or the underside of submerged sticks. We found that lily pad nests contained more eggs, more clutches of different ages, and eggs distributed over a larger area than nests under submerged sticks. The difference in egg incubation temperatures between lily pad nests and stick nests varied diurnally with air–water temperature gradients. Proximity to the surface allowed lily pad nests to be significantly warmer during the day but only slightly cooler at night than nests under submerged sticks, resulting in about 10 h shorter time to hatch. The availability of lily pads for nests may greatly alter selection on sexual behaviour by males in competing for limiting nest sites of high quality, and female opportunity to exercise choice of mate. Moreover, availability of lily pads changes the role of abiotic conditions. In warm weather, males that nest under lily pads may achieve greater reproductive success than males that nest under sticks.