• Reading time:3 mins read

This week the zoo news story that caught my eye was the reintroduction of the tequila fish (Zoogoneticus tequila) back into the wild.

What could be more eye catching than a fish named after a spirit? As far as I can tell this is the only one… there is no vodka fish, no brandy fish and definitely no whisky fish. The tequila fish is a species of goodied fish (I’m not making these names up) from the Ameca River basin in south-west Mexico.

The tequila fish (picture from Chester Zoo website)

The tequila fish disappeared from the wild around 2003 following the introduction of guppies to its original habitat of Mexican rivers & springs. A 2003 three study found less than 50 adults alive in a single isolated pool and these are competing with 300 guppies for food and resources. It doesn’t take a mathematician to see where this story leads. A mix of invasive species, water pollution and water extraction managed to kill off the population in the wild.

This is where you find the tequila fish in its natural habitat

Conservationists at Chester Zoo have been working with the Michoacana University of Mexico to reintroduce 1500 fish to a serious of springs in the Teuchitlán River in the state of Jalisco in south-west Mexico. That is 30x more fish than were found in that pool.

What is amazing is how they managed to do it… In 1998 Chester Zoo sent over 5 breeding pairs to the Mexican University. That is only 10 fish to do all this work. They got to it and over the next 15 years founded a new captive colony of Tequila fish.

However, a colony in tanks isn’t the same as a viable reintroduction population to the university build large artificial ponds and took out 40 males and 40 females to start another new colony, this time specifically for reintroduction. In four years, this went from 80 fish to 10,000 fish which provides the stock for reintroduction.

Reintroduction is a vital element of the work that zoos undertake. Being able to keep a captive stock for reintroduction may be the only way for some species to withstand the onslaught of ecological destruction our generation is seeing.

This project has been cited as an International Union for Conservation of Nature (IUCN) case study for successful global reintroductions. Recent studies suggest the fish are thriving in the wild.

Leave a Reply