A word from the Sustainable Agriculture Facilitator (May 2026)
In July 2023, a quiet but exciting discovery at Toms Lake near Booligal changed what we thought we knew about biodiversity in the lower Lachlan – and reminded us how much there still is to learn when we slow down and really look after Country.
During fish surveys in April and July 2023, an endangered olive perchlet was found living in this ephemeral wetland system. The olive perchlet is a tiny fish – only about five to six centimetres long – transparent, feisty and carnivorous despite its size. It’s listed as endangered in western NSW, and until recently only one population was believed to exist in the Lachlan River system, near the Lake Brewster weir pool.
Finding olive perchlet at Booligal came as a real surprise.
Fish ecologist Dr Adam Kerezsy (Dr Fish Contracting), who has worked across the Lachlan catchment for nearly 30 years, was sampling Toms Lake as part of unrelated environmental water monitoring when his nets revealed something unexpected. What started as a “that’s odd” moment quickly became something much bigger. Genetic testing later confirmed that the Booligal fish weren’t just wanderers from Brewster – they are a separate population that had likely been there all along, quietly surviving out of sight.
This discovery has big implications for how we think about floodplains and water management. Olive perchlet are floodplain specialists, meaning they thrive after big flow events, moving into wetlands and lakes when rivers connect to the landscape. The major floods of 2022-23 likely helped reveal this population, highlighting just how important natural flooding is for supporting life beyond the main river channel.
Because Toms Lake and nearby wetlands naturally dry out, there was an urgent need to protect the fish. Working closely with landholders, NSW Fisheries, the Murray Darling Basin Authority and researchers, 74 olive perchlet were carefully relocated to a secure refuge dam nearby. This site was chosen because it offers protection from drying, carp and future flood risks. It’s a great example of what can happen when local knowledge, science and collaboration come together for a common goal.
This story doesn’t stop with fish.
In 2026, students from Hay Public School will be learning about the olive perchlet as part of place‑based education linked to the Future Rural Leaders Program, delivered in partnership with Riverina Local Land Services through the Climate Smart Agriculture Program. Using the olive perchlet as a local case study, students will explore the connections between climate, water, farming and biodiversity – and how good land management supports both people and nature.
For young people growing up on the Hay Plains, discovering that an endangered species has been quietly persisting right on their doorstep is powerful. It shows that sustainable agriculture isn’t just about what we produce, but how we care for Country so it can keep supporting life into the future.
Sometimes the most important stories aren’t the biggest or loudest. Sometimes they’re small, nearly invisible – and they remind us why paying attention really matters.
Did you know?
- Olive perchlet grow to just 5-6 cm long, making them one of the smaller native fish in the Murray–Darling Basin
- They’re almost transparent, which is why they’re sometimes called “glassfish”
- They rely on floodplain wetlands, booming in numbers after big floods
- Until 2023, only one population was known in the Lachlan; the Booligal fish doubled what we thought existed
- Losing floodplain habitats means losing species like the olive perchlet.
This project is supported by the Australian Government through funding from the Natural Heritage Trust under the Climate-Smart Agriculture Program and delivered by Riverina Local Land Services, a member of the Commonwealth Regional Delivery Partners panel.
This article was written by Jade Auldist. Jade is the Sustainable Agriculture Facilitator for the Riverina region. Her role supports farmers, industry and community groups (including Landcare Groups) to adopt new and innovative sustainable agriculture practices.
For further information on this article, please contact Jade at jade.auldist@lls.nsw.gov.au.
