The blackspotted topminnow, Fundulus olivaceus, is a species of fish in the family Fundulidae: the topminnows and North American killifishes. It is native to the south-central United States, where it is known from the drainages of the Mississippi River from Illinois to the Gulf of Mexico and as far west as Galveston Bay. This species lives in clear streams with fast currents and sand or gravel substrates. It can often be found near the thick vegetation along the banks of the streams. It is omnivorous, consuming some plant matter along with a main diet of insects and other arthropods.