The Halloween darter (Percina crypta) is a small freshwater fish native to North America.

At a maximum standard length of 101 mm (4 in), males are slightly larger than females, and both sexes develop distinctive orange barring on the edge of the first dorsal fin during the breeding season.

The holotype had been collected in 1994 by B. J. Freeman, J. Devivo, J. W. Garrett, M. J. Zieg, R. E. Jenkins, J. S. Boyce, L. M. Hartle, and M. Flood from the Chattahoochee River near Sautee Nacoochee, Georgia and Nora Mill Dam.

The clade is a polytomy, however, meaning that clearer evolutionary relationships among members was not discernible based on the utilized methods.

[2] Halloween darters have terete (cylindrical or slightly tapering) bodies, with males longer than females.

Females' eyes are also dark, and their upper and lower jaws range in color from olive-black to pale yellow.

It is also present in the Uchee Creek, a tributary that joins the Chattahoochee River near the fall line in Alabama.

[1] This fish is typically found in fast-flowing sections of small and medium-sized rivers over bottoms composed of gravel, cobble or rock, often in areas where hornleaf riverweed (Podostemum ceratophyllum) grows.

[6] It is insectivorous, consuming a variety of aquatic insects such as mayfly nymphs and larvae of midges, black flies, and caddisflies.

Offspring hatch in June, with juveniles growing to more than half the maximum adult length by October.

This mussel releases larvae called glochidia that lodge in the gills of suitable fish to develop into juveniles.

It typically occurs in deep, fast-flowing sections of waterway, and damming of the rivers has altered the hydrological conditions and siltation.

[1] In 2010, the United States Fish and Wildlife Service was petitioned by a coalition of environmental organizations (Alabama Rivers Alliance, Center for Biological Diversity, Clinch Coalition, Dogwood Alliance, Gulf Restoration Network, Tennessee Forests Council, West Virginia Highlands Conservancy and activists Tierra Curry and Noah Greenwald) to list 404 aquatic species under the Endangered Species Act of 1973, including the Halloween darter.

They included the Halloween darter based on the perceived threats of habitat destruction, as well as insufficient regulatory measures currently in place to protect the species.