The saltmarsh topminnow occurs sporadically in marsh habitat along the coast of the Gulf of Mexico, from Galveston Bay, Texas, to
Escambia Bay, Florida (Peterson et al. 2003). This species occurs in very small populations or is simply absent from the reports of most
fish studies of the northern Gulf of Mexico. The Galveston Bay population represents the most eastern extent of the range of this species
and is separated from the next recorded instance of this species which is in central Louisiana. Recent research confirms that there is a direct
link between abundance and coastal saltmarsh habitat embedded within a reduced range of estuarine salinity (Lopez et al. 2010).
Coastal development, levee and canal construction, pollution, and other threats can cumulatively imperil saltmarsh habitat.