This study aimed at the identification of minimally invasive stress biomarkers in the skin mucus of fish submitted to distinct intensities (mild and most intense) of different types of stress i.e., overcrowding (OC), repeated net-handling (NET) and hypoxia (HYP). Fish trials were conducted in triplicate tanks and four fish per tank were randomly sampled for MS analysis. This work also aimed to disclose most significant changes in signaling and metabolic pathways involved in the stress response in this immunity related biofluid. The presented data-driven knowledge study may ultimately contribute for the improvement of species-specific welfare management protocols, towards a sustainable aquaculture.