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Tecopa Pupfish

Tecopa pupfish was a subspecies of Amargosa pupfish that got extinct by the year 1970 due to habitat modification and the introduction of non-native species.


Scientific Classification

Kingdom Animalia
Phylum Chordata
Class Actinopterygii
Order Cyprinodontiformes
Family Cyprinodontidae
Genus Cyprinodon
Species C. nevadensis
Subspecies Cyprinodon nevadensis calidae

Quick Info

Historical epoch Modern (went extinct around 50 years ago)
Size 1 to 1.5 inches
What did they eat Blue-green algae, Mosquito larvae
Color Breeding males – Bright blue coloration
Breeding females – Olive brown with six to ten vertical stripes
Lifespan 2 years
Habitat In the outflows of Tecopa Hot Springs, Mojave Desert, California
Predators Humans and Large fish
Adaptation Their color enabled them to blend into their environment; had the ability to sustain water temperature up to 108°F

Physical Characteristics

Their head was blunt with a small oblique terminal mouth and a full row of tricuspid teeth. Their dorsal fins were closer to the tail, and it had a set of six fin rays (lepidotrichia) out of which the pelvic fin was small or missing at times.


Depending on the water temperature, the fish would produce two to ten offspring per year. The males were also capable of breeding.


The Tecopa pupfish was related to the group of killifish, diversely found in North America. These fishes probably evolved during the mid-Pleistocene period wherein the pluvial lakes occasionally filled up the now-desert region. However, the fish got isolated when the lakes got evaporated over the years. After six years of study, Dr. Robert Rush Miller described the subspecies C. n. calidae in 1948.


The fishes resided in Tecopa Hot Springs which was about 2 miles from north of Tecopa town in Inyo California at an elevation of 1411 feet. The spring’s popularity triggered the extinction event during the 1950s and 1960s, causing alteration to the pupfish habitat due to the construction of bathhouses and the diversion of outflows.

The northern and southern hot springs outflows were merged in 1965, causing swifter currents that resulted in downstream water temperatures to rise above sea level, much beyond to which pupfish could adapt. These alterations made way for related Amargosa River pupfish to travel upstream, thereby hybridizing with the Tecopa pupfish.

In 1966, Miller discovered that the population of this fish was wiped out at Tecopa Hot Springs while the last confirmed specimen of Tecopa pupfish was collected on February 2, 1970. The process of delisting the fish from the endangered list was started by the United States Fish and Wildlife Service after a futile survey in 1972 and 1977. It was finally declared extinct in 1981 after an extensive search over 40 locations.

Published on February 9th 2017 by under Fish.
Article was last reviewed on 16th September 2019.

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