In terms of its intended functionality, a zebrafish facility has much in common with a typical mammalian laboratory animal facility. The facility must be equipped in such a way that it controls and maintains environmental conditions, limits the spread of pathogens, and facilitates care as well as research workflow. Beyond these basic features, however, there are few similarities. Many of the differences between fish and mammal facilities have to do with water-the medium that sustains life in any aquatic facility. Fish facilities are dynamic entities that revolve around water, which both delivers (oxygen, minerals, food, etc.) and removes (wastes, pheromones, etc.) materials to and from the fish. Consequently, and above all, fish facilities need to be outfitted to handle water in a wide variety of ways.