Abstract: The machine according to the invention comprises a channel which is:constituted by two shaped panels giving it an open bottomed V-shaped section and which are associated with relative spacing adjustment members,provided with spraying conduits and overlapping plates closing off its top part,and associated with an endless conveyor comprising thrust bars brought successively by the conveyor in a transversal position in the channel passage section.The machine according to the invention finds an application in the sorting and grading of fish of the Salmonidae family.