Basic information on the role of vitamin K in fish was described in relation to dietary intake. Vitamin K in the fish tissues was mainly concentrated in the liver and gonads, with a small amount in muscles. There was a difference in the concentration of vitamin K between demersal and pelagic fish depending on the habitat and between cultured fish and wild fish. The composition and content of vitamin K in the gastrointestinal tract which were very similar to those of the food consumed differed in the tissues, suggesting that all the vitamin K in food was not transferred to the tissues of fish. There was no clear indication that vitamin K deficiency affected the growth rate or mortality in fish, although it was reported that vitamin K deficiency caused anemia, prolonged prothrombin time, histopathological changes and bone abnormalities. Therefore, more studies are required to determine the role of vitamin K in fish.