Based on physical features, Kataws, along the Sirena and Sireno, were the Bantay Tubig-creatures that bear likeness to human while Siyokoy are those that resemble water-creatures. Unlike Sirena, they have feet instead of tails but they have gills on their bodies and fins in their arms. These marine creatures disguises into fishermen asking for help. When approached by mortals, the Kataws drown them into the abyss.