Abstract: An apparatus for separating dead fish eggs from live fish eggs is designed to automatically interrogate the degree of opaqueness of each egg in a batch of fish eggs. A selector individually separates an individual fish egg from the batch and injects the separated egg into a fluid stream for delivery past an optical interrogator. Dead fish eggs which display a high degree of opaqueness are optically detected and are hydraulically separated from live eggs which show a low degree of opaqueness. The optical interrogator delivers a light from a light source conveyed through fiber optics to the fluid stream in which the eggs are injected. An electronic detector generates a first pulse for live fish eggs and a second pulse for dead fish eggs. The second type of pulse activates a hydraulic fluid switch which causes the dead fish eggs to be deposited in a separate receptacle by changing the flow direction of the fluid stream.