Fish: During spring and summer 2011, sampling from 14rainbow trout (O. mykiss) farms in Kohgiluyeh and BuyerAhmad Province (located in North West of Iran) was
done. 280 rainbow trout (20 fish from each farm, 10-200 geach) suspected of having streptococcosis/lactococcosisfrom these farms with a water temperature of 15-19°C wereexamined for the presence of the etiological agent of thedisease. Moribund fish with external and internal bodyhemorrhages, abdominal distension and exophthalmiawere euthanized with a blow to the head and usedimmediately for bacteriological examination.