A shrimp grading machine sorts progressively smaller sized shrimp as they fall through the mechanism. Plural pairs of parallel grading rollers are inclined from an upstream inlet end to a downstream outlet end. Graded shrimp are rejected by and will not pass through the gap between horizontally adjacent rollers and thus pass off the end of the grader. A mechanism allows all of the gaps between the horizontally spaced rollers to be simultaneously adjusted.
