Masubizu are an aquatic wukai. They are said to show up near ancient shrines that are located near important waterways and bodies of water that are important for the surrounding towns, villages, animals, and plant life. Those familiar with the customs of these shrines are said to initiate a small but respectful ritual in which they ask for the Masubizu to show up and protect the waterway allowing for bountiful schools of healthy fish and clean water.
These fish spirits are fairly elusive, like many wukai, and seeing one is considered both good fortune for the area and those who observe it from the nearby shine, as they do not always appear when summoned. They are reported as having beautiful purple-blue iridescent scales and fins that shimmer and reflect the water making them look otherworldly, accented by their elongated “whiskers” given them a sagely appearance suggestive of their ancient origins.