Pupfish

Description

Pupfish are ray-finned fish with striking coloration. The Devils Hole pupfish (Cyprinodon diabolis), for example, is bright blue with purple accents. The White Sands pupfish has yellow and orange fins. Most pupfish are very small, some less than an inch (2.5 centimeters) in length.

Range

Pupfish are found in isolated aquatic habitats in the southwestern United States. Individual species are known to live in very small localities. The Devils Hole pupfish lives in only one area that is three-by-five feet across.

When Ice Age lakes that covered a large part of the Southwest began to dry up, pupfish were confined to small areas with poor water quality. In order to survive, the various species became highly adapted to withstanding conditions that would kill most other fish. The desert pupfish (Cyprinodon macularius eremus), for example, can live in water temperatures up to 110 degrees Fahrenheit. Other species tolerate huge swings in temperatures or salt content three times higher than ocean water.

Diet

Pupfish feed on a variety of things, including algae, plants, aquatic invertebrates, and insects.

Life History

The Devils Hole pupfish lives in a relatively constant habitat, so it can breed year-round. The mating system is polygynous, so a male breeds with many females, and a male may prevent other males from breeding with a female. When larvae hatch, they are less than a centimeter long. The offspring reach full reproductive maturity at 8 to 10 weeks old. A Devils Hole pupfish may live between 6 and 12 months. Others, like the Comanche Springs pupfish (Cyprinodon elegans), live for one to two years.

Conservation

Many pupfish species have incredibly low numbers and are federally listed as endangered. It’s natural for pupfish to occur in low numbers because their habitats can’t accommodate large populations. However, their small populations make them more vulnerable to extinction, and even slight threats to their habitats are major problems. Pollution and invasive species affect some species. Pupfish living in spring-fed environments are at risk from excessive groundwater withdrawal, which can dry up their habitats.

Fun Fact

The Ash Meadows Amargosa pupfish (Cyprinodon nevadensis mionectes) of Nevada can live in as little as a half-inch of water.

Sources

Sonoran Desert Conservation Plan, Pima County

Texas Parks & Wildlife Department

Tohono Chul Park

U.S. Fish & Wildlife Service