During our stay in Switzerland, which took place from August 30th until September 1st, we visited the Centre for Fish and Wildlife Health at the University of Bern. The aim of this stay was to see the interesting scientific workplace and to manage immunohistochemical analyses of tissues from intensively cultured rainbow trout (Oncorhynchus mykiss), probably affected by Proliferative Kidney Disease (PKD). In addition, we also discussed the optimization of intensive European perch (Perca fluviatilis) farming with our Swiss colleagues. At the end of our stay in Switzerland, we visited the Percitech company, which is the largest European producer of perch by intensive aquaculture using RAS.