What is "fathead minnow"

n. A small freshwater fish of the minnow family, ''Pimephales promelas'', native to North America.

The fathead minnow (Pimephales promelas), is a species of temperate freshwater fish belonging to the Pimephales genus of the cyprinid family. The natural geographic range extends throughout much of North America, from central Canada south along the Rockies to Texas, and east to Virginia and the Northeastern United States. This minnow has also been introduced to many other areas via bait bucket releases. Its golden, or xanthic, strain, known as the rosy-red minnow, is a very common feeder fish sold in the United States and Canada. This fish is best known for producing Schreckstoff (a distress signal).