All praise be to Allah Alone, and peace and blessings be upon His Messenger, and his family and Companions.
If the case is as mentioned,
then you have to remove the fish scales from your hands when performing Wudu'. Your Wudu’ is invalid with a barrier, such as the fish scales and the like, that prevent water from reaching the skin.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.