Fathead Minnow Breeding Structure

Fathead minnows, frequently called rosy reds, are the most common type of minnow used for bait. Fatheads are light yellow in color because they lack body pigment and they grow to be 2.6 to 2.8 inches in length.

  1. Time Frame

    • Mature fatheads spawn during their second year, beginning in spring when the water temperature reaches 60 degrees Fahrenheit. Spawning ends in the middle of August, and females spawn numerous times during the season.

    Features

    • A month before spawning, the male fathead minnow develops two rows of dark colored breeding tubercles that simulate small horns on his head. On his back -- behind his head and in front of the dorsal fin -- a soft spongy pad appears.

    Significance

    • The male fathead selects a nest in shallow water under an object such as a rock, log or branch. The female lays eggs that stick to the underside of the nesting object and then goes away. The male fertilizes the eggs and spends his time guarding them from predators. Males massage the eggs with their back pad for oxygenation. The male continues to protect the nest until all eggs have hatched. The eggs hatch in five to 15 days, depending on water temperature.

    Fun Fact

    • Fathead minnows get their name from the enlarged head of the breeding male.