Abstract

A group of minnows( Pimephales promelas )imported from USA developed a bacterial septicaemia. Yersinia ruckeri was isolated from kidney of affected fish. The strain was sorbitol positive and could be differentiated from formerly known European isolates. The minnows were intended to be retailed as bait-fish for fishermen, and therefore represent a serious source for dissemination of the pathogens in river systems.