In this article, I ask how a virus associated with Atlantic salmon farms in British Columbia (BC) can reveal geographies of aquaculture, ecological encounters, and colonial entanglements within the bodies and blood cells of fish. Piscine orthoreovirus (PRV) travels through supply chains, ocean currents, and ecological interactions, and causes salmon to become at risk of ruptured blood cells and organ damage. This article proposes that PRV can be interpreted as a form of industrial waste that reinforces geographies of toxicity across multiple scales. I first situate the emergence of aquaculture in BC within colonial histories that continue to transform the coastal straits into contested sites of state-making. I then outline how multiple forms of life, ecological encounters, and unique hydrological conditions become entangled with industrial practices, giving rise to novel pathogenic proliferations. I end by describing how the appearance of yellow salmon hints at the potentially far-reaching presence of PRV, and I look to the bodies of salmon to consider how the expanding PRV footprint transforms regional ecologies and contributes to emergent toxic geographies of settler-colonialism. In forging connections between settler-colonialism, industrial landscape-making, and pathogenicity, I highlight how microbes can reflect and reinforce settler-colonial structures of dispossession. Moreover, in proposing that pathogens can be understood as components of industrial toxicity, I contribute to a reimagining of what industrial toxicants are and the forms they might take.