Methods and systems for processing fish are provided which enable cutting of the fish and removal of the viscera without damage to either the viscera or the remaining fish product. The systems may include an adjustable cutting device to cut the belly in a particularly unobtrusive manner and/or an adjustable gutting device to severe a gullet of the fish from the fish body and to gather and remove the viscera without significant damage to the viscera or the remaining fish product. Extractors for severing the connection between the gullet and the fish are also provided to assist in removal of the viscera, including the gonads. Vacuum head assemblies for cleaning a cavity of the fish after the viscera is removed are also provided.