Public interest in animal welfare and compliance with animal welfare standards in aquaculture in Switzerland is growing steadily as consumers become more aware of issues such as product quality and animal welfare. Good animal welfare requires the absence of pain, fear, thirst, and hunger, although these conditions occur temporarily in nature under normal living conditions. What should hence be required for fish in aquaculture? Recent publications already provide initial answers to these questions. However, further research is urgently needed. The present project will design a model that can be used to estimate the well-being of fish in Swiss aquaculture. It will enable research to assess fish welfare in a standardized way and at the same time help fish farmers with individual self-monitoring.