All fi sh tumours in our diagnostic material collected in 1992–2005 in the National Veterinary and Food Research Institute EELA* were analysed. The total number was 48 tumours from nine wild fish species, farmed rainbow trout and four aquarium fish species. Most tumours were found in northern pike. Of the 19 tumours found in pikes, 13 were skin lymphomas diagnosed in pike from brackish water. Of the other tumours in pike, two were epithelial and four mesenchymal. Seven tumours were found in pike perch. Four of them were lymphomas and three mesenchymal tumours. Two lymphomas were likely thymic in origin. Four epithelial and two mesenchymal tumours were found in rainbow trout. Of the three tumours in breams, two were mesenchymal and one was epithelial. Tumours were sporadic in other fish species.