Fathead minnows are a common source of additional food for fish. Fatheads can tolerate lower oxygen levels than most game fish. They have a short life span of 2-3 years and reproduce frequently after water temperatures reach approximately 60 degrees. They can be omnivores but normally eat more zooplankton than algae. It takes 4-5 months for a young fathead to become sexually mature. Consequently, in Wisconsin, a newly hatched fathead will not spawn in the summer it was born because it becomes mature after the water temps have gotten too cold for spawning. Eggs of fatheads are sticky and the male directs the female to deposit them on the underside of some structure he has cleaned and prepared as a nest. These eggs will hatch in about 5 days and the resulting minnow fry leave the nesting area after 2 days of protection by the male. It is often said that fatheads spawn 4 times in a year. That is a bit misleading. Nearly all of a population goes through spawning in early May when water temperatures are appropriate. However, after that first spawning, females release eggs intermittently throughout the summer, with less and less frequency until mid- August. The amount of eggs present in a lake or pond after mid-August is minimal.