Shellfish reefs are among the most threatened coastal ecosystems in the world, with over 85% lost worldwide. Declines in their extent and condition have been implicated as contributing towards fisheries declines in some regions. Subsequently, connectivity with these complex, coastal landforms can increase fish abundance and diversity across estuarine seascapes. Understanding the influence of remnant oyster reefs on fish communities is vital in understanding what the loss of these ecosystems has on fish and fisheries. We surveyed fish assemblages in Wallis Lake, NSW using baited (to quantify broader, landscape effects) and unbaited (to quantify habitat-specific effects) underwater video stations. Quantifying habitat-specific effects allows for specific drivers to be identified that are unique to the ecosystems throughout the system. Patterns in fish assemblages were best explained by the distance of sites to remnant oyster reefs, followed by the depth of the site and the area of seagrass nearby. Total fish abundance, target fish species abundance and fish species richness were all highest at sites nearer to remnant oyster reefs. These results very strongly support the notion that maintaining the few remnant reefs that remain, and expanding their extent through restoration, has significant and positive effects on fish across entire seascapes.