What to do in Las Vegas when the sensory impact of the Strip begins to wane? Glitz and glamor are all on conspicuous display as fountains dance in the face of ever disappointing water stores behind nearby Hoover Dam. Visiting cities in the American Southwest can be a jarring experience in water terms – golf courses and man-made party boat lakes speckle the seemingly never-ending urban sprawl.

Away from the lights, noise and costs of the Strip exist a plethora of outdoor activities – Hoover Dam, Lake Mead, Red Rocks, Valley of Fire, Mt. Charleston but a few options. Today’s post concentrates on some of the unique species of life to be found in the various oasis springs found 1-2 hours west of Vegas among the desert basin area of the Amargosa Valley. In some of these springs, various species of pupfish live, their only home in the world. These fish include some of the rarest found today. The fish, like other animals and plants found around the oases, are survivors. One has to, in order to survive the climate and environment in which they call “home”.

The most famous of the pupfish is the Devils Hole pupfish – Cyprinodon diabolis. These fish – the number fluctuates with the year between 40 and 400 – live in the opening of a water-filled cavern over 400 feet deep. The opening is about 6 feet by 18 feet, though only a part of the opening is where you find the fish. These pupfish and a visit to them comes later in a separate post.

TAXONOMY

Biological taxonomy can be quite daunting. The pupfish in the Death Valley region – Death Valley is the next valley east from the Amargosa – come in several different species with most existing in the various springs and marshes. They lie within the order Cyrpinodontidae – note that taxonomical listings of the thousands of species remain not only complex, but ongoing with revisions made al the time. Cyprinodotidaiformes fossils date back to the Oligocene epoch – 25-40 million years ago – though most fossils found come from the more recent Miocene – 10-25 million years ago.

continental drift

Included within the order are the various killifish species – the pupfish are among these – and live-bearing fish, such as the guppy. The distribution of the order corresponds to plate tectonics and the breakup of Gondwana. Found in widely separated areas is cited as evidence the order to be more ancient than the fossil record. The thought goes that the order lived contemporaneously with the dinosaurs or three times earlier than the oldest fossils found. Plate movements then carried the freshwater fishes to their various present-day locations with the breakup of Gondwana 140 million years ago. So, continental drift results in the vast separation of the various species.

While continental drift can account for some species – Orestias, for example – to inhabit altiplano areas of the Andes while others occur in Southeast Asia, Africa and various other parts of the world. The killifish – the term comes from the Dutch word kil meaning small stream – find their homes in a wide variety of watery homes with an extreme variation of water and environmental conditions. Some species occur in areas of seasonal temporary waters. These species – annual killifish – live brief lives not longer than a year laying eggs in a substrate which can literally dry up. The eggs go into a resting state hatching when the rains of wet season return – roadside ditches, culverts, meadows, temporary ponds. Most hatch with the initial rains, though some hold off in case of a false onset of season.

DEATH VALLEY REGION CYPRINODON SPECIES

About 10% of all cyrinodontiform species are noted as being extinct or endangered and including all species of pupfish found in or around Death Valley. The species colonize marginal habitats easily degraded by human interactions and introduced exotic species – like sport fish. Problems like these plus the high localized nature of their distribution – here, in single springs, ponds or marshes – adds to the threat of extinction.

Males of these species are aggressive territorially.  They defend their breeding sites against others. This behavior early discovers likened to the playful nature of puppies, hence the generic name, pupfish. Pupfish can hybridize with other species of pupfish. The pupfish also have a fast evolutionary ability to diversify. The ability to diversify scientists believe is secondary to the unique ecological conditions within which they live.

Death Valley pupfish can evolve 5 to 10 times faster than average allowing them to survive in the harsh conditions imposed by the desert. In other areas – San Salvador Island in the Bahamas (Christopher Columbus’ New World landfall) and Labo Chichancanab on the Yucatan peninsula of Mexico – evolution occurs 50 to 130 times quicker than all other pupfish! One species, Cyrpinodon pachycephalus lives and breeds in waters 114° F year-round.

We have seen how the order Cyprinodontidae has formed in disparate areas of the world – continental drift. The different species of Death Valley pupfish once were thought to be a single species. They derived from the Ice Age Lake Manly covering some 620 square miles of today’s desert about 185,000 to 128,000 years ago. With desiccation over time, the pupfish became isolated into separate ponds and began to evolve divergently. Multiple species never coexisted naturally in the same habitat.

SPECIES VERSUS SUBSPECIES

By definition, the term subspecies implies populations living in different areas which vary in size, shape, or other physical characteristics, but which can successfully interbreed – hybridize. In the wild, subspecies do not interbreed due to geographic isolation or sexual selection. The differences between subspecies in the Amargosa region appear much less distinct than differences between species – note the following two subspecies which are a little more obviously different than those in the Amargosa Basin.

Kingdom, Phylum, Class, Order, Family, Genus, Species, in order of increasing specificity. This seems to imply “species” is the narrowest category when categorizing living things, but that’s not quite true. Many species also have subspecies, a designation given to genetically distinct and geographically isolated populations which can still interbreed with the main body of the species when their ranges overlap.

Hybridization – the interbreeding between subspecies – can extend the range in which a species lives. But the process also can overrun the original subspecies causing the loss of biodiversity.

DEATH VALLEY PUPFISH

Salt Creek Pupfish

Within Death Valley, the two main subspecies include Cyprinodon salinus – Salt Creek pupfish – and Cyprinodon milleri – Cottonball Marsh pupfish. The Salt Creek pupfish live in Salt Creek located a few miles north of Furnace Creek. A side road takes off from the main highway a little over a mile north of Beatty Junction. The road then leads southwest to a boardwalk paralleling the creek.

Atop the boardwalk, visitors can look into the waters of the creek to see the pupfish. The gravel road remains closed since 2022 floods played havoc with the trail. Supposedly, the Park Service planned to redo the trail and reopen it in the fall of 2024. That was one year ago. Major flooding took place on many of the Park roads this monsoon season – late summer. That probably means monies the Park has will go to road re-openings, though the Park notes a possible reopening late 2025? One can walk or bicycle into Salt Creek in the meantime. This means a walk of little over a mile one-way to the road end.  The boardwalk trail extends for another half mile.

Cottonball Marsh Pupfish

The Cottonball Marsh pupfish live downstream from their Salt Creek cousins. The marshes are directly west of the Park employee housing area just north of Furnace Creek. To visit the marshes, one needs to take care.  You must walk cross country for four mile one-way from the Salt Creek trailhead – head due south and stay on the west side of the valley – or slightly more than four miles if coming straight west from Highway 190. Make sure the day is cooler and carry plenty of water. Both species are very closely related, so Salt Creek is a much better option for viewing the fish.

AMARGOSA PUPFISH

Saratoga springs Pupfish

At the south end of Death Valley are two other subspecies – the Saratoga Springs pupfish, Cyprinodon nevadensis nevadensis – and the Amargosa pupfish, Cyprinodon nevadensis amargosae reside in pools of the Amargosa River, a seasonal river at best. The Saratoga Springs pupfish occur naturally only at Saratoga Springs. The spring pool in size consists of a diameter of 30 feet with a depth of 3 to 6 feet. From the main pool, overflows pour water into several other ponds over an area of 4 to 6 acres. Water temperature is a constant 82-84° F, but that can vary with the seasons between 50 and 120° F. Juvenile fish have not been noted in the spring itself.

One population of these fish went to Lake Tuendae, an artificial pond created at Zzyzx, just outside of Baker – Zzyzx has an interesting history of its own. It is unclear whether those fish have continued to live and breed in their new environment.

Access to Saratoga Springs is off California Highway 127 fourteen or fifteen miles north of Baker – or about the same distance on the same highway south of Shoshone. Then drive west on an unpaved road for about five miles to Saratoga Spring Road which heads straight north for 2.7 miles. High-clearance vehicles remain recommended on this road because of washboard. You cross over the Amargosa Riverbed which can be impassable if the river flows. The road finally at an intersection, twists to the west for just over another mile to end at the spring and its marshes.

Amargosa River Pupfish

The Amargosa pupfish occur in two distinct areas where the lower Amargosa River flows year-round. There is a dry stretch of some 10 miles between. One site found lies around Tecopa on the upstream side. Here temperatures can exceed 97° F though the fish prefer water temperatures near 86° F. Seasonal water temperatures run from 50 to 100° F. The downstream range of the fish lies near Saratoga Springs.

Note that between the hamlet of Shoshone and the Dumont Dunes – an area just east of the access to Saratoga Springs off CA 127 – this region of the Amargosa River is included as a part of the National Wild and Scenic Rivers System. Here, perennial flows run supported by groundwater coming from the Spring Mountains located on the west side of Las Vegas more than 40 miles away. The Amargosa River drainage occupies two-thirds of the 8,500-square-mile area of the Death Valley watershed.

SHOSHONE PUPFISH – Cyprinodon nevadensis nevadensis

This specific species was first described in 1889 by Carl and Rosa Eigenmann. In 1977 and 1980, reports described the species as extinct. The numbers dwindled again in 1986 to less than 20 possibly because of Western Mosquitofish – Gambusia affinis – getting into the outflow creek. Since the removal of the mosquitofish, numbers of the pupfish have rebounded. Thanks to the efforts of the property owner, Susan Sorrells, and a group of working biologists and local landowners, after a couple pupfish were discovered in an irrigation ditch. Ponds were constructed below the spring pool and cattails threatening to cover the water surface were removed.

SHOSHONE PUPFISH TODAY

The Shoshone pupfish, like other pupfish in the area, live in a very small locale – only in the spring and four other constructed pools. Like the other species, this pupfish can also survive a wide range of extreme conditions. While they can survive the harsh conditions, reproductive tolerance limits are much narrower – 75 to 86° F with 82 to 84° F being ideal.

Alterations to temperature outside their favored ranges result in reproductive failure. Fertilized eggs do, however, gain resistance to environmental stress only hours after being lain. Like other pupfish, the Shoshone pupfish develops rapidly after hatching, reaching sexual maturity after only four to six weeks. They multiply quickly to make up for a short lifespan of not much more than a year.

Like all pupfish species, Cyprinodon nevadensis nevadensis feeds on blue-green algae, cyanobacteria and occasionally small invertebrates. They feature long guts characteristic of aquatic herbivores. A diurnal species, the Shoshone pupfish feeds throughout the day and becomes inactive at night. And while, like the other pupfish of the Southwest, they are well adapted to the harsh environment in which they live, they do remain vulnerable to changes whether it be to natural or man-made changes. A former local swimming pool has been removed to further protect the fish after incidents where chlorinated overflows killed some fish. Also, the springs remain the water source for those people living in the hamlet of Shoshone as well as the only habitat for the fish.

GENETICALLY DIFFERENT?

Some questions remain whether the Shoshone pupfish is genetically distinct from the Amargosa pupfish. If not, then the Shoshone pupfish is truly extinct or was never genetically distinct to start. And if they are genetically distinct, they are one of the most threatened fish in California.

A VISIT TO SHOSHONE SPRINGS

To visit the pupfish, after stopping at the Shoshone Museum, drive off California Highway 178 at the Shoshone Inn onto the road marked “Old State Hwy”. Look carefully behind the inn and you can find a pen holding a couple of desert tortoises to observe munching away on their lettuce meals. Drive a little further and you will find the pupfish pools on the west side of the road.

The largest of the ponds occurs at the bottom of a channel leading down from the spring. This refuge pond sits 16 feet by 49 feet with banks of three-square bulrush planted on the sides. A path leads to a series of five pools. A back up water supply lies in place in case flow from the single uncapped spring fails. The whole area, on our visit, was under construction of a new area dedicated also to the Amargosa vole, a small mammal which lives on as precariously as the pupfish.

Looking out over the pond, you will notice hundreds of the pupfish swimming happily around. You might think, what is all the fuss about, but remember, this is the only place in the world they exist. Even if they are genetically the same as the Amargosa pupfish, those fish remain equally endangered. This remains the easiest place to observe the pupfish in real life.

Beyond the fish and the tortoises, there is also another species here, the Amargosa vole, also once thought to be extinct. Within the Shoshone Springs complex, work is undergoing led by the University of California at Davis to give them a home where they can hopefully recover.

PUPFISH OF ASH MEADOWS NATIONAL WILDLIFE REFUGE

Ash Meadows National Wildlife Refuge offers another excellent stop to observe pupfish in the wild along with Shoshone and Salt Creek-Death Valley. There are two distinct sub-species living in the spring pools within the refuge – Warm Springs pupfish, Cyprinodon nevadensis pectoralis and the Ash Meadows pupfish, Cyprinodon nevadensis mionetes. The pupfish live among a complex of 30 perennial springs and sloughs set among some of the hottest and driest North American deserts along with other species of plants, snails and insects which only occur here.

WARM SPRINGS PUPFISH

The Warm Springs pupfish live in six small springs within an area of less than a square mile. None of the springs pumps out little more than a gallon per second of water. That water disappears after slightly more than one mile into the ground. Like other pupfish, these have a wide tolerance to saline levels due to a unique ability to rapidly adjust serum osmotic concentration of ions, preventing water loss. They are short-lived – 2 to 4 years – and quickly reach maturity within 2 to 4 months. With colder waters, the pupfish can go dormant during the winter thus extending their lives to about three years. And like all Cyprinodon nevadensis, the Warm Springs pupfish spawn throughout the year peaking during the spring.

Primary threats to the population include habitat alteration whether from groundwater extraction for mining or agricultural purposes – the main reason the wildlife refuge became established – or from the introduction of predatory or competing non-native species like mosquitofish, crayfish, bullfrogs.

The Warm Springs pupfish lie in the North Indian, South Indian, North Scruggs, South Scruggs, Marsh and School springs. Habitat renovations to remove invasive species is an ongoing process with each of these springs restricted to public vehicle access. The number of fish varies from spring to spring with the most fish noted at the two Scruggs Springs.

ASH MEADOWS AMARGOSA PUPFISH

Ash Meadows Amargosa pupfish occur in six springs and in streams below – King’s Pool, Crystal, Longstreet, Rodgers, Jackrabbit and Fairbanks springs. The threats here are the same with their Warm Springs cousins – groundwater extraction (recent bore holes were recently denied by the BLM in 2023) and invasive species.

other amargosa fish species

In addition to the pupfish, the Amargosa River hosts three separate populations of Amargosa Speckled Dace – Rhinichthys osculus nevadensis, situated in Oasis Valley near Beatty, Ash Meadows, and the Amargosa Canyon. An interesting revelation concerns the genetic makeup of these fish, indicating an unexpected level of connectivity along the river.

Particularly noteworthy is the genetic blend observed in the speckled dace population of the Amargosa Canyon, incorporating traits from both the Oasis Valley and Ash Meadows populations. This suggests that during significant flood events, speckled dace are capable of traversing considerable distances along the Amargosa River, covering nearly 100 miles from Beatty to below Tecopa.

While rare in the Amargosa River. They are a bit more plentiful in Willow Creek, a tributary of the Amargosa to the southeast of Tecopa – near the China Ranch Date Farm.

VISITING ASH MEADOWS NATIONAL WILDLIFE REFUGE AND DEVILS HOLE

development of the refuge

Truman’s 1952 proclamation made 40 acres around the cavern entrance part of Death Valley National Monument – the Monument became a National Park in 1994. Reasoning for the proclamation noted a “peculiar race of desert fish … which is found nowhere else in the world, evolved only after the gradual drying up of the Death Valley Lake System isolated this fish population from the original ancestral stock that in Pleistocene times was common to the entire region.” The Park Service neglected the Hole for much of the first 15 years afterwards. It was only threats by developers in the Amargosa Valley when preservation of the Hole and its unique pupfish began taken more seriously eventually leading to a US Supreme Court decision ending in part the water depletion attempts.

In 1984, secondary to political movements and new threats to develop Ash Meadows into something like what has occurred in the nearby Pahrump Valley, the Ash Meadows National Wildlife Refuge developed. Ash Meadows NWR represent one of the first organized to protect endangered species – of which there are several species beyond the Devils Hole pupfish at play here. The land was acquired by the Nature Conservancy the year before with funds reimbursed by the federal government.

getting there

Ash Meadows sits west of the Longstreet Inn on Nevada Highway 373. Turn east off 373 onto Spring Meadows Road about a mile north of the Inn-Casino which is located on the California-Nevada border. Four mile of dirt road – graded and accessible by normal vehicles except for periods of rain where mud can factor in – leads to the Ash Meadows NWR Visitor Center. Another access routes you from the south off Bell Vista Road coming west from the north end of Pahrump or east from Death Valley Junction, about three miles south from the Longstreet Inn. Either way is about four miles to the Center.

The Center includes stories about the various endangered species in the refuge. At the time of our visit, it was closed because of the 2025 government shut down. There is a 0.9-mile boardwalk we walked behind the Center which loops across the alkali floor to Crystal Springs. The boardwalk sets up high enough so you cannot really see any pupfish – here, they are Ash Meadows Amargosa pupfish, Cyprinodon nevadensis mionectes – without binoculars. Afternoon winds made possible sightings even more difficult on our visit. The trail loops back to the Visitor Center along the springs outlet before recrossing the alkali.

devils hole

Driving further on the road from the Center, you turn south until you find an intersection with the road heading east continuing on to Devils Hole – about a half mile further. For Devils Hole, park on the side and walk in on a trail-road to the fenced-off area around the collapsed cave-pool. Walking through a squirrel cage meant to keep visitors and fish separate, you come to an observation point some 40-foot above the pool. Note the array of monitoring equipment set out to keep track of visitors, water levels, and water chemistry. Without a good pair of binoculars, you will not be able to see the fish, but you still gain a good sense of isolation.

Something to note; if you see white patches on the surface of the shelf, these are for the purpose of gathering eggs which, because of the season, would not normally hatch. Those eggs are gathered up and taken to the Ash Meadows Fish Conservation Center to replenish their stocks. You might notice the occasional pupfish skittering across the pads.

For a comprehensive study of the Devils Hole pupfish and the various political struggles to preotect them, read Kevin Brown’s excellent Devils Hole Pupfish.

King’s Pool

Backtrack and turn south – this is the road in from Bell Vista Road – another 0.3-mile brings you to the road going east to the Point-of-the-Rocks. This is the best spot where you can observe the pupfish – again Cyprinodon nevadensis mionetes. A short 0.5-mile boardwalk takes you through meadows created by several springs, the most obvious being at King’s Pool. Here, from the edge of the pool, look carefully down under the water to see the pupfish feeding on algae. You can also note the occasional Western Mosquitofish – Gambusia affinis. The trail continues a short way to a hilltop viewpoint looking out over the surrounding desert.