Two recent projects have been implemented to trial improvements to fish habitat in ACT rivers. Each project tackles different environmental problems and conditions. The first was using concrete reef balls tm and ‘Cod Caves’ to provide habitat in a reach highly constrained by anthropogenic influences on the Molonglo River. The second was Engineered Log Jams (ELJs) to create habitat and mitigate the impacts of a sand slug in a section of the Murrumbidgee River. The aim of both projects was to improve habitat for native fish in the reach particularly large bodied native fish. The reaches that had Cod Caves were compared with nearby reaches congested with willows and reaches cleared of willows and flood debris. Monitoring of the Cod Caves over four years found significantly fewer carp in the improved reaches than either the uncleared or cleared reaches, and that both Golden Perch and Murray Cod were more common in the improved reaches. Monitoring of the ELJs has found high numbers of Murray Cod juveniles and adults in the immediate vicinity of the structures compared to other habitats available nearby. Results suggest that when applied to relevant riverine conditions the habitat improvement techniques trialled were highly successful at improving conditions for native fish.