How group housing for laboratory zebrafish improves welfare and research quality by meeting shoaling behavioral needs.
Zebrafish social housing is a welfare intervention with strong evidence and clear practical benefit. As shoaling fish, zebrafish rely on social cues for normal behavioral regulation, and isolation produces chronic stress that is both a welfare problem and a scientific confound. Group housing is feasible in standard laboratory settings with appropriate tank design, and the welfare benefits — reduced stress hormones, normalized behavior, and improved immune function — also translate to more reproducible experimental outcomes. The alignment of welfare and scientific quality provides a strong case for universal adoption of group housing standards.