The fathead minnow is a small, hardy, and widely cultivated member of the Cyprinidae family of minnows that is commonly used as bait, and it is an important forage species for gameﬁsh. It is also commonly used in toxicity studies.
IdentificationThe fathead minnow has a stubby, deep, compressed body with a short head that is ﬂat on top. The snout is blunt. The mouth is small and slanted and possesses pharyngeal teeth. The body is generally dull in color, being dark olive or gray above and fading to muted yellow to white below. The scales become larger toward the tail and smaller toward the head, and the lateral line curves downward and is incomplete.
There is a dark spot at the middle of the anterior dorsal rays, the caudal rays have dark outlines, and the leading edge of the pectoral ﬁns is black. There is also a stout half-ray at the front of the dorsal ﬁn. There are no barbels, but breeding males develop tubercles on their snouts and become darker.