Over 580 fish species are known for Port Jackson, site of the first British colony of New South Wales. When the British arrived in January 1788 they encountered Aboriginal people who gained a substantial part of their diet from fish. Aboriginal fishing technologies (e.g. spears, shell fishhooks and small canoes) were documented by colonial writers. The British brought metal fishhooks, seine nets and larger boats, and after AD1788 fishing was important to both Aboriginal people and colonists. Given the diversity of fish in Port Jackson, and differences between Aboriginal and colonial fishing technologies, our paper discusses archaeological and documentary evidence for the impact of technology on the types of fish caught by Aboriginal people and colonists before and after AD1788. We compare archaeological fish bones from Aboriginal sites in coastal Sydney with those from the Quadrant historical site in Broadway, Sydney, and discuss methodological challenges raised by these kinds of analyses for Sydney regional archaeology. Technology explains some fish bone assemblage variability but colonisation, cultural attitudes, commercialisation and urbanism are also important.