Zygonectes dispar Agassiz, 1854 The Starhead topminnow (Fundulus dispar) is a native United States species that ranges from the Ouachita River drainage in Louisiana, the Big Black river in Mississippi, and extends northward into the Mississippi River and Lake Michigan basins to the southern Michigan and southern Wisconsin areas.

[1] The Starhead topminnow is endangered due to the removal of aquatic vegetation and the continued development of land that infringes on its habitat.

There are records of the Starhead Topminnow from the Fox River Chain of Lakes, Pecatonica, Kankakee, central and lower Illinois, and lower Wabash river drainages, as well as the LaRue-Pine Hills Ecological Area.

[3] In 2024, after decades of being presumed extirpated, an isolated population of starhead topminnows was discovered in Iowa in a slough of the Mississippi River.

During mating season, the largest recorded number of eggs laid by a single female is 33.

[7] Starhead topminnows have been found to prefer to lay their eggs among vegetation or on the floor of the environment.

[3] The Wisconsin Department of Natural Resources has classified the Starhead topminnow as endangered with the state rank of S2.