The survival of the native Canterbury mudfish is in doubt as population numbers continue to decline towards extinction.
The release of the New Zealand Threat Classification System report today shows the mudfish population is at a nationally critical level.
Conservation Minister Eugenie Sage said most known mudfish were found on private land on the Canterbury Plains and were severely impacted by agriculture.
"They are found in still or very slow flowing, meandering streams with deep pools and associated wetlands, spring fed streams, stock-water races, and drains. Basically, land-based aquatic environments, whether natural or human-made," Ms Sage said.
"With a mere 10 percent of New Zealand's wetlands remaining, it's sad but not surprising that the loss of aquatic and other wetland habitat has had a major impact on Canterbury mudfish and other wetland-dependent indigenous freshwater fish."
The report details the latest conservation status of the country's 76 known freshwater fish species.
More than 95 percent of threatened native fish species, including the Canterbury mudfish, are from the Galaxiidae family.