The Macquarie Marshes, NSW is one of the most significant wetlands in Australia. However, the system faces a range of anthropogenic threats. Decades of water extraction have led to widespread ecological decline. Since 2007, data have been collected on fish responses to environmental flows delivered to the Marshes system. These 'artificial floods' are aimed at restoring the fish communities by restoring the natural flow regime. The information from this research is used to guide ongoing delivery of environmental flows for the best ecological outcomes.