This chapter explores animal housing through the ethnographic lens of salmon aquaculture, and aquaculture through the lens of animal housing. It draws inspiration from new work on domestication that seeks both to explore and to expand conventional notions of what this might be about. The approach blends material semiotic versions of science and technology studies (STS) with what is often referred to as "lateral theory" in anthropology. The chapter focuses on the salmon domus or the salmon assemblage; it explains what it consists of, how it gets made, and how far it extends. Salmon farming is at once a large-scale industrial enterprise and the most recent turn in the human history of domestication. Salmon aquaculture marks a change, not only in the human history of animal domestication, but also of a simultaneous extension in the history of industrial food production from the terrestrial to the marine.