Disease outbreaks were observed in fish of 10 to 200
g in farms in North West of Iran (Kohgiluyeh and Buyer
Ahmad Province). The disease occurred during spring
and summer when water temperature increased above
14°C. Sluggish movement, darkening of body, bilateral
exophthalmia sometimes together with cataract and
hemorrhage, abdominal distention and prolaps of anal
area with hyperemia/hemorrhage were observable in
most affected fish. Also, accumulations of bloody fluids
in abdominal cavity, hemorrhage in intestinal lumen were
seen in dissection examination.