Rainbow trout are among the most commonly farmed fish in Europe and North America. Developing reliable welfare indicators for trout has advanced aquaculture welfare science.
Rainbow trout have been valuable model species for developing aquaculture welfare science because they are well-studied and their pain and stress responses are clearly documented. Behavioral indicators like fin damage, abnormal swimming, and reduced feeding signal welfare problems in trout populations. The strong scientific evidence for trout sentience has supported the development of welfare standards for trout farming that serve as models for other finfish species. Trout welfare improvements including lower stocking densities, better water quality management, and percussive stunning before slaughter are increasingly adopted in higher-welfare certification schemes.