Fighting for the Future of Freshwater Fish
Mexican goodeids are a family of delicate freshwater fishes highly adapted to live in specific habitats. The majority of goodeid species are either Critically Endangered or Endangered. Human activities are changing the watery environments these fish are uniquely evolved to inhabit, placing the fish populations at risk, but an action plan to halt their decline is now in place.
Goodeids in the Wild
There is a global biodiversity crisis occurring in freshwater ecosystems. An assessment in 2020 showed that 40% of freshwater fish species in Mexico are threatened. Among them are most of the 37 goodeid species still scattered across shallow freshwater zones; several goodeid species have already become extinct.
The goodeid fish family, which includes species also known as splitfins, is unique. They have distinctive reproductive biology and breeding behaviours, with the females bearing and releasing live young.
Goodeid species inhabit specific and separate water ecosystems and are highly evolved to survive within these niches. Many of the species in this family of fish are microendemic, meaning that they have a limited range, often restricted to a single watershed or lake. This makes them particularly susceptible to the effects of pollution, invasive species and climate change.
Splitfin Success
The future of this emblematic and diverse fish family is threatened by deforestation, chemical run-off from agriculture and industry, water extraction, dams and hydroelectric developments and more. Michoacán University’s Mexico Fish Ark, which was established in 1998, has been monitoring and conserving these species for decades.
Chester Zoo has provided technical and financial support to their projects since 2000. This collaboration has led to important conservation successes. In 2022, 1,500 tequila splitfins, which were extinct in the wild, were reintroduced to the Teuchitlán River in the state of Jalisco in south-west Mexico. This was the first time a fish listed by the IUCN as ‘Extinct in the Wild’ has been successfully reintroduced in Mexico, and represents a landmark moment in the conservation of freshwater fish, which are often overlooked by the general public.
More recently, Chester Zoo and the Mexico Fish Ark have begun a collaboration with the Goodeid Working Group, IUCN SSC Freshwater Conservation Committee and SHOAL Conservation to expand research and conservation efforts across all goodeid species. Together, we have launched a 10-year plan to increase legal protections for goodeid habitats and to stabilise or grow goodeid populations.
Restoring Freshwater Environments
The first stages of the plan include thorough surveys of freshwater environments in Mexico. We are building a more accurate picture of where goodeid fish live, how many of each species survive and what condition these populations are in.
Conservationists in the field are undertaking regular assessments of goodeid habitats, looking at ecosystem health and the level and nature of any threats to these areas. The project partners are also creating a database so up-to-date information can be shared with conservationists. This data, drawn from regular studies, will help conservationists identify threats and decide how best to mitigate them, and to help restore the environment in and around key freshwater habitats.
Ex-situ goodeids cared for in aquariums and by private keepers could play an important part in the survival of this fish family. We are building links with various individuals and groups to share knowledge about best practice for goodeids in human care, including breeding successes.
The research from the field will also give us valuable information on the best conditions for the care and breeding of goodeids outside their natural habitats.
Our priority is to sustain goodeid populations already in the wild, but the plan includes backup measures. We are looking into the possibility of re-introducing more fish to boost wild numbers, and the feasibility of creating new ponds to support goodeid population growth.
Ultimately, this plan will preserve the vivid diversity of these small but significant fish species. By protecting goodeids, conservationists also protect their freshwater habitats, providing a boost for biodiversity and human wellbeing.
Specialists
Find out more about the conservation experts working on this project.
Head of Ectotherms
Assistant Team Manager - Amphibians