River modification to meet human demands has profoundly altered connectivity in Australian waterways, with substantial consequences for native fish populations. Barriers constructed for water storage and regulation restrict fish movement, limiting access to essential habitats and hindering fish from completing their life cycles. At the same time, water abstraction for irrigation and other uses can result in the entrainment of millions of native fish into diversion channels and pumping infrastructure each year. Addressing these contrasting challenges requires different yet complementary management approaches. While modern fish protection screens can minimise unwanted fish movement into water infrastructure, fish passage structures aim to restore connectivity and facilitate movement past instream barriers. Both approaches have demonstrated considerable potential, but their effectiveness depends on appropriate design, implementation, and consideration of local environmental conditions and fish communities. Several lessons have been learned, and future opportunities remain to improve fish protection and connectivity in human-modified rivers across Australia.