After being declared extinct in the wild 18 years ago, the tiny tequila splitfin fish has been successfully reinstated to the rivers of Mexico’s Jalisco state.

Thanks to conservationists from Chester Zoo and the Michoacan University, 1,500 of the 3-inch-long fish have been restored to the springs of the Teuchitlán River. 

The tequila fish vanished from their natural habitat back in 2003 as a result of a combination of water pollution and the arrival of invasive, exotic fish species.

However, the fish are once again thriving, with the International Union for the Conservation of Nature calling the scheme a case study for global reintroductions.

In fact, the Union has noted, freshwater habitats are some of the most threatened — with their species going extinct faster than their terrestrial or marine counterparts.

Team members said that the success of the rewilding program has given them a blueprint for how to recover these fragile fish species from Mexico. 

In fact, the team are already well into a second rescue mission on the Teuchitlán River, focussing this time on the presently-extinct-in-the-wild golden skiffia. 

Scroll down to see the video

After being declared extinct in the wild 18 years ago, the tiny tequila splitfin fish (pictured) has been successfully reinstated to the rivers of Mexico's Jalisco state

The tiny Tequila Splitfin Fish (pictured), which was declared extinct 18 years ago in Mexico, has been successfuly restored to Mexico’s Jalisco river.

Thanks to conservationists from Chester Zoo and the Michoacan University, 1,500 of the 3-inch-long fish have been restored to the springs of the Teuchitlán River (pictured)

Thanks to conservationists from Chester Zoo and the Michoacan University, 1,500 of the 3-inch-long fish have been restored to the springs of the Teuchitlán River (pictured)

The tequila fish (pictured) vanished from their natural habitat back in 2003 a a result of a combination of water pollution and the arrival of invasive, exotic fish species.

In 2003, the tequilafish (pictured) disappeared from their habitat due to a mixture of water pollution and introduction of exotic fish species.

STATISTICS FOR TEQUILA SPITFIN FISH

Species: Zoogoneticus tequila

Max. length: 2.7 inches (70 mm)

Habitat: Teuchitlán River, Mexico

Conservation status Endangered 

Colouration:Olives with mottle body

Diet: Zooplankton

‘This is the first time an extinct species of fish has ever been successfully reintroduced in Mexico and so it’s a real landmark for conservation,’ said biologist Omar Dominguez of the Michoacan University of Saint Nicholas of Hidalgo in Mexico.

“It has set an important precedent in conservation of many endangered and extinct fish species that live in our country. But we rarely pay attention to them.

The tequila-splitfin is a species that scientists have used for many years to study evolution, biogeography, and the live bearing reproduction methods of fishes. It could not be left alone.

It also has an even greater impact on the environment. The environment in which the fish lives has also been improved.

“The springs have been declared healthy, and all residents can enjoy the beautiful area again.

“Meanwhile locals, especially schoolchildren are fully accepting an ongoing education program, which is changing how many act toward the freshwater environment around them.

This, he added, is ‘absolutely vital if we’re to ensure long-term change.’

The restoration programme began in earnest in 1998, when researchers at the Michoacan University’s Aquatic Biology Unit received five pairs of tequila fish from Chester Zoo that were delivered by the British aquarist Ivan Dibble.

They were later used to establish a new colony within the laboratory of the university. The lab was maintained and increased over the subsequent 15-year period.

To prepare them to be reintroduced into the wild, 40 male and 40 female tequila splitfins from the laboratory colony were first released into large artificial ponds at the university — thereby exposing them to a ‘semi-natural’ setting.

These fish had to deal with more realistic situations like fluctuations in prey, possible competitors, parasites as well predators such as birds, snakes, or turtles. 

The tequila fish more than rose to meet these challenges, however, and in just four years had increased their numbers to some 10,000 individuals — a fraction of which were then used to repopulate the Teuchitlán River.

The tequila fish (pictured) are once again thriving in the wild, with the International Union for the Conservation of Nature calling the scheme a case study for global reintroductions

Pictured: Tequila Fish (pictured). The International Union for the Conservation of Nature calls the scheme an example of global reintroductions.

The success of the rewilding programme (pictured), the team added, has created a 'blueprint for what works in terms of recovering these delicate fish species in Mexico'

The team said that the program’s success (pictured) had created a blueprint of what worked in Mexico for recovering delicate fish species.

Prior to the return to the wild, the researchers spent two year conducting field surveys around the Teuchitlán River — assessing local levels of various invertebrates, fish, parasites, phytoplankton and zooplankton — to identify the best release sites.

The team also undertook outreach work with the local communities to improve awareness of the river’s aquatic habitats and highlight the value of helping to maintain healthy water sources.

This was followed by a long-term monitoring program to monitor water quality and habitat quality. The team also trained local residents.

The researchers have been undertaking outreach work with the local communities to improve awareness of the river's aquatic habitats and highlight the value of helping to maintain healthy water sources. Pictured: the team educate local school children about tequila fish

They have also been working with communities to raise awareness and promote the benefits of healthy water resources. Pictured: The team educates local schoolchildren about Tequila Fish

The researchers are already well into a second rescue mission on the Teuchitlán River, focussing this time on the presently-extinct-in-the-wild golden skiffia (pictured)

The researchers are already well into a second rescue mission on the Teuchitlán River, focussing this time on the presently-extinct-in-the-wild golden skiffia (pictured) 

'This is the first time an extinct species of fish has ever been successfully reintroduced in Mexico and so it’s a real landmark for conservation,' said biologist Omar Dominguez of the Michoacan University of Saint Nicholas of Hidalgo in Mexico. Pictured: a tequila splitfin

‘This is the first time an extinct species of fish has ever been successfully reintroduced in Mexico and so it’s a real landmark for conservation,’ said biologist Omar Dominguez of the Michoacan University of Saint Nicholas of Hidalgo in Mexico. Pictured: a tequila splitfin

'The tequila splitfin has, for many years, been used by scientists to study the evolution, biogeography and live bearing reproduction techniques of fishes and is a very important species. We could not stand back and allow it to disappear,' said Professor Dominguez

‘The tequila Splitfin is a species that has long been important in the study of evolution, biogeography, and living bearing reproduction methods for fishes. Professor Dominguez stated that we could not allow the species to die.

“This moment is crucial in the fight for species conservation. It is a real privilege to have helped save this charismatic little fish,’ said Chester Zoo’s curator or lower of vertebrates and invertebrates, Gerardo Garcia.

‘Following years of hard work by our partners at the Michoacan University of Mexico, the wild population is, thankfully, now thriving — they’re breeding naturally at a tremendous rate. 

‘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.

‘This is also a great example of how good zoos can play a pivotal role in species conservation,’ he continued.

‘Not only has Chester Zoo been involved technically and financially, [but] the breeders, which became the founding population for the reintroduction of the tequila splitfin, originated at Chester Zoo.

‘Without the zoo population keeping the species alive for many years, this fish would have been lost forever. It’s humbling to think that a small population, being cared for by aquarists in Chester, has now led to their revival in the wild.’ 

The restoration programme began in earnest in 1998, when the Michoacan University's Aquatic Biology Unit received five pairs of tequila fish from Chester Zoo that were delivered by the British aquarist Ivan Dibble. The fish were then used to found a new colony in the university's laboratory, which was taken care of and expanded over the course of the next 15 years. Pictured: one of the colony of tequila splitfin fish

The restoration programme began in earnest in 1998, when the Michoacan University’s Aquatic Biology Unit received five pairs of tequila fish from Chester Zoo that were delivered by the British aquarist Ivan Dibble. The fish were then used to found a new colony in the university’s laboratory, which was taken care of and expanded over the course of the next 15 years. Pictured: one of the colony of tequila splitfin fish

'This is an important moment in the battle for species conservation. It is a real privilege to have helped save this charismatic little fish,' said Chester Zoo's curator or lower of vertebrates and invertebrates, Gerardo Garcia. Pictured: the team work to release the tequila fish in the wild

‘This is an important moment in the battle for species conservation. Gerardo Garcia (Centre Zoo curator, lower of vertebrates and insects), said it is an honor to have saved this little fish. Pictured: The team works to release the Tequila Fish in the Wild

Thanks to conservationists from Chester Zoo and the Michoacan University, 1,500 of the 3-inch-long tequila splitfin fish have been restored to the springs of the Teuchitlán River

Thanks to conservationists from Chester Zoo and the Michoacan University, 1,500 of the 3-inch-long tequila splitfin fish have been restored to the springs of the Teuchitlán River

According to researchers, the Earth is currently experiencing an’man-made’ sixth mass extermination that includes the “biological annihilation” of wildlife.

Five mass extinctions have occurred in the history of humanity, and scientists believe that we may be witnessing another.   

One 2017 paper stated that a biological annihilation of animals in the recent past has caused the sixth mass extermination and warned the planet towards a global crisis. 

Scientists say the first significant extinction since dinosaurs is due to human greed and destruction.

Two vertebrates with a backbone have become extinct each year for over a century.

Around 41% of all amphibian species are at risk and 25% of mammals face imminent extinction.

An estimated 8.7 Million plant and animal species exist on the planet. Only 86 Percent of terrestrial species, and 91% of marine species have been discovered.

Among the species we know are 1,204 mammal; 1,469 bird; 1,215 reptile; 2,100 amphibian and 2,386 different fish species.

1 414 insect, 2187 mollusc and 732 crustacean are also at risk.

For the 2017 Red List update, more than 25.000 species were assessed and were deemed ‘threatened. 

Also, the number of at-risk invertebrates has also risen. 

Scientists have predicted that insects will become extinct within the next 100 years because of a crippling decline in their numbers.   

With the Anthropocene, the geological age in which human activity is the predominant influence on the climate and environment, the dawning of mass extinction occurs.