In November 2020 a mortality episode (30%) in juvenile Siberian and Russian sturgeons ( Acipenser baerii , Brandt, and A . gueldenstaedtii , Brandt & Ratzeburg) and GUBA hybrid sturgeons ( A. gueldenstaedtii × A. baerii) occurred in a hatchery in Northern Italy, associated with severe coelomic distension and abnormal reverse surface swimming. The fish were reared in concrete tanks supplied by well water, fed at 0.4% of body we...