The fathead minnow has an alarm that launches a material called Schreckstoff when certain cells are injured in an assault. After that, this released compound is identified by the predator fish who then will certainly hide or dart away. This system aids fathead minnows recognize possible predators. The fathead's main predator is the north pike, and this chemical acknowledgment ability assists the minnow recognize its predators.
The generating period of the fathead minnow flies June through July, with some spawning as early as mid-May, and also prolonging to early August. They like a temperature variety of 50 - 70 degrees Fahrenheit, as well as spawing occurs in temperature levels around 64 degrees Fahrenheit. The male looks after eggs that the female deposits in a nest. Typically, a male fathead minnow will certainly take over a nest website that is currently in use. It chooses sites that already consist of eggs, and also the even more eggs in the nest, the more probable the existing male will certainly be challenged by a new male fathead minnow. This sort of actions is called allopathernal treatment, where one man displaces the other male. Men aerate the eggs, they eliminate unhealthy eggs, as well as they shield eggs from predators such as crayfish. By "switching over out" the men, it permits greater survival of the eggs, as the brand-new males that take over are "fresher" and a lot more fit maybe, to advance the activity of protecting the eggs. Each male minnow defends the website for three to 5 weeks, enabling a "changing of the guard". The eggs hatch in roughly five days.