Sunday 19 May
Devil’s Hole pupfish (Cyprinodon diabolis)
What’s the World’s Favourite Species?Find out here.
Devil’s Hole pupfish fact file
- Find out more
- Print factsheet
Devil’s Hole pupfish description
Found only in a single desert spring in Nevada, USA, this tiny fish has the most restricted range of any vertebrate (2). The smallest of all pupfish, this unique species lacks pelvic fins and the distinctive barring so common among other pupfish (2) (4). The fins are large and rounded with dark edges, and the dorsal and anal fins are located far back on the body (5). As with all pupfish, the sexes of this species are differently colored. Males are silvery with iridescent neon-blue sides, which change to metallic green or golden under different angles of light (4) (6). The female is smaller and more yellowish-brown, with the young resembling females (4) (7).
- Length: up to 25 mm (2)
Devil’s Hole pupfish biology
This diurnal fish feeds on algae, diatoms, and invertebrates (3). Mating is polygynous, following a consort-pair mating system in which the male closely follows behind an egg-bearing female for up to one hour, with the pair periodically descending to spawn in the algae (4) (7). Males will prevent other male competitors from interfering by blocking the intruder with his body but exhibits little aggressive behaviour (7). Although capable of breeding throughout the year, most of the species’ reproductive effort is concentrated in April and May (4). It takes an average of seven days for eggs to hatch, with the young reaching sexual maturity eight to ten weeks later (7), but growth and development are dependent on food supply (3). This fish rarely lives for longer than 12 months (7).Top
Devil’s Hole pupfish range
Confined to Devil’s Hole, which is a deep, isolated pool in Ash Meadows, part of the arid Death Valley region of Nevada, USA (3) (7). The entire population feeds and breeds in an area of approximately 20 square metres (8).Top
Devil’s Hole pupfish habitat
Devil’s Hole is a rock-bound spring pool that lies about 15 metres below the land surface, constituting a limestone rock shelf about 0.3 metres below the water surface and a very deep subterranean reservoir (4) (7). This species occupies the upper 30 metres of the pool, frequenting the limestone shelf, which provides sunlight exposure and access to food, as well as a site for spawning (3) (7). The water temperature stays a constant 32 to 34 ºC (4) (7).Top
Devil’s Hole pupfish statusTop
Devil’s Hole pupfish threats
With such a restricted range, the population of Devil’s Hole pupfish has been small for a long time, but was first observed to be undergoing declines in the 1960s. This decline was largely attributed to water-management practices that pumped out groundwater for crop irrigation and desert development, thereby reducing the water level in Devil’s Hole; and water loss continues to pose a major potential threat to the species (3). Since these fish feed and breed on the limestone shelf just a few inches below the water’s surface, lowered water levels could easily push the Devil’s Hole pupfish to extinction. Nature also seems to have worked against the pupfish, with flash floods in 1973 and an earthquake in 1978 carrying large amounts of debris into the pool and creating water disturbance, which scoured away much of the algae on which they feed and in which they spawn (4). Again, as much as half of the population (total population varies from 200 to 800 depending on the time of year (7)) was destroyed in 2004 when, in a terrible twist of irony, flash floods unexpectedly forced scientific research equipment designed to preserve the endangered species into the pool (9)!Top
Devil’s Hole pupfish conservation
In the 1970s the Devil’s Hole pupfish was the focus of a famous U.S. Supreme Court water rights case, brought by the federal government against a farming concern that was pumping water from wells associated with Devil’s Hole (5). In 1976 the courts decided in favour of the fish, upholding a lower court order to establish a minimum water level in Devil's Hole that would ensure the continued existence of the pupfish (4). In 1984, The Nature Conservancy (TNC) was able to purchase the surrounding land and create Ash Meadows National Wildlife Refuge to protect the area’s unique fauna (5) (7). Artificial lights have been installed over the shallow breeding shelf to stimulate diatom and algae growth to provide more food to the pupfish, and routine census taking was also instituted (4).
Attempts have been made to relocate some of the population and induce spawning in other environments such as the Steinhart Aquarium in San Francisco, but have mostly been unsuccessful (7). The idea is that spreading the fish out would minimize the possibility of the species being wiped out completely by a single catastrophic event (7) (10). Fortunately, efforts to rear the fish in a tank near Hoover Dam have proved successful, with an original sample of just eight individuals having grown to over 74 (7) (10). However, individuals here have exhibited different growth patterns to those in the wild and no one is sure if these fish could survive if released into the wild (7) (10). Wildlife biologists are therefore planning to build another refugium that better replicates the actual conditions of water temperature, oxygen content, sunlight and algae in Devil’s Hole (10). These findings only serve to demonstrate how this pupfish, as perhaps one of the most geographically isolated organisms in the world, is highly adapted to its unique environment (7) and, despite significant conservation efforts, remains in an extremely precarious position (4).Top
Find out more
For more information on the Devil’s Hole pupfish see:
Animal Diversity Web:
Baugh, T. & Deacon, J.E. (1983) The Most Endangered Pupfish. Freshwater and Marine Aquarium, 1983: 0. Available at:
This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
- Anal fin
- In fish, an unpaired fin on the under surface of a fish, behind the anus.
- Active during the day.
- Dorsal fin
- In fish, the unpaired fin found on the back of the body.
- Pelvic fin
- In fish, the pair of fins found on the underside of the body.
- In animals, a pattern of mating in which a male has more than one female partner.
- A separate tank which shares water and filtration with the main aquarium, or an isolated area that has escaped ecological changes elsewhere and so provides a suitable habitat for a relict species.
IUCN Red List (September, 2008)
- Burnie, D. (2001) Animal: The Definitive Visual Guide to the World’s Wildlife. Dorling Kindersley, London.
U.S. Endangered Species Act (January, 2006)
Baugh, T. and Deacon, J.E. (1983) The Most Endangered Pupfish. Freshwater and Marine Aquarium, 1983. Available at:
eNature: National Wildlife Federation (February, 2006)
- Rivers, I.L. (1994) Fishes and Fisheries of Nevada. University of Nevada Press, Nevada.
Animal Diversity Web (February, 2006)
FishBase (February, 2006)
Rake, L. (2005) Scientists have a devil of a time with pupfish. Las Vegas Sun, 2005: 0 - 0. Available at:
Rogers, K. (2004) Pupfish hang on with a little help from biologists. Las Vegas Review-Journal, 2004. Available at:
MyARKive offers the scrapbook feature to signed-up members, allowing you to organize your favourite ARKive images and videos and share them with friends.
Terms and Conditions of Use of Materials
Copyright in this website and materials contained on this website (Material) belongs to Wildscreen or its licensors.
Visitors to this website (End Users) are entitled to:
- view the contents of, and Material on, the website;
- download and retain copies of the Material on their personal systems in digital form in low resolution for their own personal use;
- teachers, lecturers and students may incorporate the Material in their educational material (including, but not limited to, their lesson plans, presentations, worksheets and projects) in hard copy and digital format for use within a registered educational establishment, provided that the integrity of the Material is maintained and that copyright ownership and authorship is appropriately acknowledged by the End User.
End Users shall not copy or otherwise extract, alter or manipulate Material other than as permitted in these Terms and Conditions of Use of Materials.
Additional use of flagged material
Green flagged material
Certain Material on this website (Licence 4 Material) displays a green flag next to the Material and is available for not-for-profit conservation or educational use. This material may be used by End Users, who are individuals or organisations that are in our opinion not-for-profit, for their not-for-profit conservation or not-for-profit educational purposes. Low resolution, watermarked images may be copied from this website by such End Users for such purposes. If you require high resolution or non-watermarked versions of the Material, please contact Wildscreen with details of your proposed use.
Creative commons material
Certain Material on this website has been licensed to Wildscreen under a Creative Commons Licence. These images are clearly marked with the Creative Commons buttons and may be used by End Users only in the way allowed by the specific Creative Commons Licence under which they have been submitted. Please see http://creativecommons.org for details.
Any other use
Please contact the copyright owners directly (copyright and contact details are shown for each media item) to negotiate terms and conditions for any use of Material other than those expressly permitted above. Please note that many of the contributors to ARKive are commercial operators and may request a fee for such use.
Save as permitted above, no person or organisation is permitted to incorporate any copyright material from this website into any other work or publication in any format (this includes but is not limited to: websites, Apps, CDs, DVDs, intranets, extranets, signage, digital communications or on printed materials for external or other distribution). Use of the Material for promotional, administrative or for-profit purposes is not permitted.