Native fish populations in the Murray Darling Basin are estimated to be at 10% of pre-European numbers. One significant cause of declines is barriers to fish movement, which can lead to population fragmentation and loss of access to key habitat. Barriers can be created by physical instream structures, cold water pollution and changed hydrological conditions. This project will use a biohydrodynamics laboratory to fill knowledge gaps about: the swimming ability and behaviour of key native fish species; their susceptibility to altered environmental conditions; and their ability to adapt to these altered conditions. The results will inform the design of fishways around physical barriers and the management of cold water releases from dams.