Group housed zebrafish show lower levels of stress and anxiety when they undergo procedures than those who are housed singly.
![A row of plastic fish tanks holding zebrafish at a laboratory. The tanks are tall and narrow, and sit next to each other in numbered racks. The whole aquarium has a blue hue to it. You can see many zebrafish in each tank, socially housed.](/sites/default/files/styles/image_16_9/public/2022-01/Fish%20tanks%20in%20an%20aquarium%20blue.jpg?itok=REe5e3Fe)
Group housed zebrafish show lower levels of stress and anxiety when they undergo procedures than those who are housed singly.
Key issues for the humane killing of laboratory animals.