Friday, August 22, 2025

Tequila fish, once declared extinct in wild, is thriving through breeding program

A fish species that shares its name with Mexico’s most famous alcoholic beverage has been successfully reintroduced to a river in Jalisco after disappearing from the wild almost 20 years ago.

The reintroduction occurred after the aquatic biology unit of the Michoacana University bred thousands of tequila fish (Zoogoneticus tequila) during a period of 15 years after receiving five pairs of the species from the United Kingdom’s Chester Zoo in 1998.

Conservationists from the university and the zoo joined forces to return more than 1,500 of the fish to the Teuchitlán River in recent years. The fish, a species named after the Tequila Volcano that grows to a maximum length of about seven centimeters, disappeared from the river in 2003 after numbers began to dwindle in the early 1990s.

Contamination of the river due to the growth of the agricultural and industrial sectors in Jalisco was largely responsible for the species’ demise.

Now, however, the pez tequila, a live-bearing fish, is thriving and breeding in the Teuchitlán River, recent studies have confirmed.

Conservationists working on the re-introduction project
Conservationists working on the re-introduction project J. Javier Alvarado Díaz Aquatic Biology Laboratory, UMSNH

Experts cited by the newspaper The Guardian say the reintroduction of the species provides a blueprint for future reintroductions of other species. A mission to return the golden skiffia – another member of the Goodeidae family of fish – to the Teuchitlán is already underway.

Before being released to the river, the tequila fish spent time in large artificial ponds at the Michoacana University, located in Morelia, Michoacán.

“This exposed them to a semi-natural environment where they would encounter fluctuating resources, potential competitors, parasites, and predators such as birds, turtles and snakes,” The Guardian reported.

“After four years, this population was estimated to have increased to 10,000 individuals and became the source for the reintroduction to the wild,” the newspaper said.

Omar Domínguez, a professor at the university, said it was the first time that an extinct species of fish has been successfully reintroduced in Mexico.

“… It’s a real landmark for conservation. It’s a project which has now set an important precedent for the future conservation of the many fish species in the country that are threatened or even extinct in the wild but which rarely take our attention,” he said.

Domínguez told the newspaper El País that the tequila fish population in the Teuchitlán River is now stable. He also said that groups of local people are monitoring the fish and cleaning up its habitat. He described them as “the guardians of the river.”

Dr. Gerardo García, curator of lower vertebrates and invertebrates at Chester Zoo, also said that the reintroduction of the tequila fish was an important milestone in the fight to save vulnerable wildlife.

“It is a real privilege to have helped save this charismatic little fish and it just goes to show that with the skill and expertise of conservationists, and with local communities fully invested in a reintroduction project, species can make a comeback from environments where they were once lost,” he said.

“With nature declining globally at rates unprecedented in human history – and the rate of extinction accelerating – this is a rare success story. We now have a blueprint for what works in terms of recovering these delicate fish species in Mexico and already we’re on to the next one – a new rescue mission for the golden skiffia is already well underway.”

With reports from The Guardian and El País 

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